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Heinrich Himmler

Heinrich Luitpold Himmler (7 October 1900 – 23 May 1945) was a German politician who was the 4th Reichsführer of the Schutzstaffel (Protection Squadron; SS), a leading member of the Nazi Party of Germany, and one of the most powerful men in Nazi Germany, primarily known for being a main architect of the Holocaust.

As a member of a reserve battalion during the First World War, Himmler did not see active service or combat. He joined the Nazi Party in 1923 and the SS in 1925, and in 1929 Adolf Hitler appointed him Reichsführer-SS. Over the next sixteen years, Himmler developed the SS from a 290-man battalion into a million-strong paramilitary group. He was known for good organisational skills and for selecting highly competent subordinates, such as Reinhard Heydrich in 1931. From 1943 onwards, he was both Chief of the Kriminalpolizei (Criminal Police) and Minister of the Interior, overseeing all internal and external police and security forces, including the Gestapo (Secret State Police). He also controlled the Waffen-SS, the military branch of the SS.

Himmler's interest in occultism and Völkisch topics influenced the development of the racial policy of Nazi Germany, and he also incorporated esoteric symbolism and rituals into the SS. He was the principal overseer of Nazi Germany's genocidal programs, forming the Einsatzgruppen and administering extermination camps. In this capacity, Himmler directed the killing of some six million Jews, between 200,000 and 500,000 Romani people, and other victims. A day before the launch of Operation Barbarossa, Himmler commissioned the drafting of Generalplan Ost, which was approved by Hitler in May 1942 and implemented by the Nazi regime, killing approximately 14 million people, mostly Polish and Soviet citizens.

Late in the Second World War, Hitler briefly appointed Himmler as military commander and later Commander of the Replacement (Home) Army and General Plenipotentiary for the administration of the entire Third Reich (Generalbevollmächtigter für die Verwaltung). Specifically, he was given command of the Army Group Upper Rhine and the Army Group Vistula. After Himmler failed to achieve his assigned objectives, Hitler replaced him in these posts. Realising the war was lost, Himmler attempted to open peace talks with the western Allies without Hitler's knowledge, shortly before the end of the war. Hitler learned of this, dismissed him from all his posts in April 1945, and ordered his arrest. Himmler attempted to go into hiding but was detained and arrested by British forces and killed himself in British custody on 23 May 1945.

Early life
Heinrich Luitpold Himmler was born in Munich on 7 October 1900 into a conservative middle-class Roman Catholic family. His father was Joseph Gebhard Himmler (1865–1936), a teacher, and his mother was Anna Maria Himmler (née Heyder; 1866–1941), a devout Roman Catholic. Heinrich had two brothers: Gebhard Ludwig (1898–1982) and Ernst Hermann (1905–1945).

Himmler's first name, Heinrich, was that of his godfather, Prince Heinrich of Bavaria, a member of the royal family of Bavaria who had been tutored by Himmler's father. He attended a grammar school in Landshut, where his father was deputy principal. While he did well in his schoolwork, he struggled in athletics. He had poor health, suffering from lifelong stomach complaints and other ailments. In his youth he trained daily with weights and exercised to become stronger. Other boys at the school later remembered him as studious and awkward in social situations.

Himmler's diary, which he kept intermittently from the age of 10, shows that he took a keen interest in current events, dueling, and "the serious discussion of religion and sex". In 1915, he began training with the Landshut Cadet Corps. His father used his connections with the royal family to get Himmler accepted as an officer candidate, and he enlisted with the reserve battalion of the 11th Bavarian Regiment in December 1917. His brother, Gebhard, served on the western front and saw combat, receiving the Iron Cross and eventually being promoted to lieutenant. In November 1918, while Himmler was still in training, the war ended with Germany's defeat, denying him the opportunity to become an officer or see combat. After his discharge on 18 December, he returned to Landshut. After the war, Himmler completed his grammar-school education. From 1919 to 1922, he studied agriculture at the Munich Technische Hochschule (now Technical University Munich) following a brief apprenticeship on a farm and a subsequent illness.

Although many regulations that discriminated against non-Christians—including Jews and other minority groups—had been eliminated during the unification of Germany in 1871, antisemitism continued to exist and thrive in Germany and other parts of Europe. Himmler was antisemitic by the time he went to university, but not exceptionally so; students at his school would avoid their Jewish classmates. He remained a devout Catholic while a student and spent most of his leisure time with members of his fencing fraternity, the "League of Apollo", the president of which was Jewish. Himmler maintained a polite demeanor with him and with other Jewish members of the fraternity, in spite of his growing antisemitism. During his second year at university, Himmler redoubled his attempts to pursue a military career. Although he was not successful, he was able to extend his involvement in the paramilitary scene in Munich. It was at this time that he first met Ernst Röhm, an early member of the Nazi Party and co-founder of the Sturmabteilung ("Storm Battalion"; SA). Himmler admired Röhm because he was a decorated combat soldier, and at his suggestion Himmler joined his antisemitic nationalist group, the Bund Reichskriegsflagge (Imperial War Flag Society).

In 1922, Himmler became more interested in the "Jewish question", with his diary entries containing an increasing number of antisemitic remarks and recording a number of discussions about Jews with his classmates. His reading lists, as recorded in his diary, were dominated by antisemitic pamphlets, German myths, and occult tracts. After the murder of Foreign Minister Walther Rathenau on 24 June, Himmler's political views veered towards the radical right, and he took part in demonstrations against the Treaty of Versailles. Hyperinflation was raging, and his parents could no longer afford to educate all three sons. Disappointed by his failure to make a career in the military and his parents' inability to finance his doctoral studies, he was forced to take a low-paying office job after obtaining his agricultural diploma. He remained in this position until September 1923.

Nazi activist
Himmler joined the Nazi Party on 1 August 1923, receiving party number 14303. As a member of Röhm's paramilitary unit, Himmler was involved in the Beer Hall Putsch—an unsuccessful attempt by Hitler and the Nazi Party to seize power in Munich. This event would set Himmler on a life of politics. He was questioned by the police about his role in the putsch but was not charged because of insufficient evidence. However, he lost his job, was unable to find employment as a farm manager, and had to move in with his parents in Munich. Frustrated by these failures, he became ever more irritable, aggressive, and opinionated, alienating both friends and family members.

In 1923–24, Himmler, while searching for a world view, came to abandon Catholicism and focused on the occult and in antisemitism. Germanic mythology, reinforced by occult ideas, became a religion for him. Himmler found the Nazi Party appealing because its political positions agreed with his own views. Initially, he was not swept up by Hitler's charisma or the cult of Führer worship. However, as he learned more about Hitler through his reading, he began to regard him as a useful face of the party, and he later admired and even worshipped him. To consolidate and advance his own position in the Nazi Party, Himmler took advantage of the disarray in the party following Hitler's arrest in the wake of the Beer Hall Putsch. From mid-1924 he worked under Gregor Strasser as a party secretary and propaganda assistant. Travelling all over Bavaria agitating for the party, he gave speeches and distributed literature. Placed in charge of the party office in Lower Bavaria by Strasser from late 1924, he was responsible for integrating the area's membership with the Nazi Party under Hitler when the party was re-founded in February 1925.

That same year, he joined the Schutzstaffel (SS) as an SS-Führer (SS-Leader); his SS number was 168. The SS, initially part of the much larger SA, was formed in 1923 for Hitler's personal protection and was re-formed in 1925 as an elite unit of the SA. Himmler's first leadership position in the SS was that of SS-Gauführer (district leader) in Lower Bavaria from 1926. Strasser appointed Himmler deputy propaganda chief in January 1927. As was typical in the Nazi Party, he had considerable freedom of action in his post, which increased over time. He began to collect statistics on the number of Jews, Freemasons, and enemies of the party, and following his strong need for control, he developed an elaborate bureaucracy. In September 1927, Himmler told Hitler of his vision to transform the SS into a loyal, powerful, racially pure elite unit. Convinced that Himmler was the man for the job, Hitler appointed him Deputy Reichsführer-SS, with the rank of SS-Oberführer.

Around this time, Himmler joined the Artaman League, a Völkisch youth group. There he met Rudolf Höss, who was later commandant of Auschwitz concentration camp, and Walther Darré, whose book The Peasantry as the Life Source of the Nordic Race caught Hitler's attention, leading to his later appointment as Reich Minister of Food and Agriculture. Darré was a firm believer in the superiority of the Nordic race, and his philosophy was a major influence on Himmler.

Rise in the SS
Upon the resignation of SS commander Erhard Heiden in January 1929, Himmler assumed the position of Reichsführer-SS with Hitler's approval; he still carried out his duties at propaganda headquarters. One of his first responsibilities was to organise SS participants at the Nuremberg Rally that September. Over the next year, Himmler grew the SS from a force of about 290 men to about 3,000. By 1930 Himmler had persuaded Hitler to run the SS as a separate organisation, although it was officially still subordinate to the SA.

To gain political power, the Nazi Party took advantage of the economic downturn during the Great Depression. The coalition government of the Weimar Republic was unable to improve the economy, so many voters turned to the political extreme, which included the Nazi Party. Hitler used populist rhetoric, including blaming scapegoats—particularly the Jews—for the economic hardships. In September 1930, Himmler was first elected as a deputy to the Reichstag. In the 1932 election, the Nazis won 37.3 percent of the vote and 230 seats in the Reichstag. Hitler was appointed Chancellor of Germany by President Paul von Hindenburg on 30 January 1933, heading a short-lived coalition of his Nazis and the German National People's Party. The new cabinet initially included only three members of the Nazi Party: Hitler, Hermann Göring as minister without portfolio and Minister of the Interior for Prussia, and Wilhelm Frick as Reich Interior Minister. Less than a month later, the Reichstag building was set on fire. Hitler took advantage of this event, forcing Hindenburg to sign the Reichstag Fire Decree, which suspended basic rights and allowed detention without trial. The Enabling Act, passed by the Reichstag on 23 March 1933, gave the Cabinet—in practice, Hitler—full legislative powers, and the country became a de facto dictatorship. On 1 August 1934, Hitler's cabinet passed a law which stipulated that upon Hindenburg's death, the office of president would be abolished and its powers merged with those of the chancellor. Hindenburg died the next morning, and Hitler became both head of state and head of government under the title Führer und Reichskanzler (leader and chancellor).

The Nazi Party's rise to power provided Himmler and the SS an unfettered opportunity to thrive. By 1933, the SS numbered 52,000 members. Strict membership requirements ensured that all members were of Hitler's Aryan Herrenvolk ("Aryan master race"). Applicants were vetted for Nordic qualities—in Himmler's words, "like a nursery gardener trying to reproduce a good old strain which has been adulterated and debased; we started from the principles of plant selection and then proceeded quite unashamedly to weed out the men whom we did not think we could use for the build-up of the SS." Few dared mention that by his own standards, Himmler did not meet his own ideals.

Himmler's organised, bookish intellect served him well as he began setting up different SS departments. In 1931 he appointed Reinhard Heydrich chief of the new Ic Service (intelligence service), which was renamed the Sicherheitsdienst (SD: Security Service) in 1932. He later officially appointed Heydrich his deputy. The two men had a good working relationship and a mutual respect. In 1933, they began to remove the SS from SA control. Along with Interior Minister Frick, they hoped to create a unified German police force. In March 1933, Reich Governor of Bavaria Franz Ritter von Epp appointed Himmler chief of the Munich Police. Himmler appointed Heydrich commander of Department IV, the political police. Thereafter, Himmler and Heydrich took over the political police of state after state; soon only Prussia was controlled by Göring. Effective 1 January 1933, Hitler promoted Himmler to the rank of SS-Obergruppenführer, equal in rank to the senior SA commanders. On 2 June Himmler, along with the heads of the other two Nazi paramilitary organizations, the SA and the Hitler Youth, was named a Reichsleiter, the second highest political rank in the Nazi Party. On 10 July, he was named to the Prussian State Council. On 2 October 1933, he became a founding member of Hans Frank's Academy for German Law at its inaugural meeting.

Himmler further established the SS Race and Settlement Main Office (Rasse- und Siedlungshauptamt or RuSHA). He appointed Darré as its first chief, with the rank of SS-Gruppenführer. The department implemented racial policies and monitored the "racial integrity" of the SS membership. SS men were carefully vetted for their racial background. On 31 December 1931, Himmler introduced the "marriage order", which required SS men wishing to marry to produce family trees proving that both families were of Aryan descent to 1800. If any non-Aryan forebears were found in either family tree during the racial investigation, the person concerned was excluded from the SS. Each man was issued a Sippenbuch, a genealogical record detailing his genetic history. Himmler expected that each SS marriage should produce at least four children, thus creating a pool of genetically superior prospective SS members. The programme had disappointing results; less than 40 per cent of SS men married and each produced only about one child.

In March 1933, less than three months after the Nazis came to power, Himmler set up the first official concentration camp at Dachau. Hitler had stated that he did not want it to be just another prison or detention camp. Himmler appointed Theodor Eicke, a convicted felon and ardent Nazi, to run the camp in June 1933. Eicke devised a system that was used as a model for future camps throughout Germany. Its features included isolation of victims from the outside world, elaborate roll calls and work details, the use of force and executions to exact obedience, and a strict disciplinary code for the guards. Uniforms were issued for prisoners and guards alike; the guards' uniforms had a special Totenkopf insignia on their collars. By the end of 1934, Himmler took control of the camps under the aegis of the SS, creating a separate division, the SS-Totenkopfverbände.

Initially the camps housed political opponents; over time, undesirable members of German society—criminals, vagrants, deviants—were placed in the camps as well. In 1936 Himmler wrote in the pamphlet "The SS as an Anti-Bolshevist Fighting Organization" that the SS were to fight against the "Jewish-Bolshevik revolution of subhumans". A Hitler decree issued in December 1937 allowed for the incarceration of anyone deemed by the regime to be an undesirable member of society. This included Jews, Gypsies, communists, and those persons of any other cultural, racial, political, or religious affiliation deemed by the Nazis to be Untermensch (sub-human). Thus, the camps became a mechanism for social and racial engineering. By the outbreak of World War II in autumn 1939, there were six camps housing some 27,000 inmates. Death tolls were high.

Consolidation of power
In early 1934, Hitler and other Nazi leaders became concerned that Röhm was planning a coup d'état. Röhm had socialist and populist views and believed that the real revolution had not yet begun. He felt that the SA—now numbering some three million men, far dwarfing the army—should become the sole arms-bearing corps of the state, and that the army should be absorbed into the SA under his leadership. Röhm lobbied Hitler to appoint him Minister of Defence, a position held by conservative General Werner von Blomberg.

Göring had created a Prussian secret police force, the Geheime Staatspolizei or Gestapo in 1933 and appointed Rudolf Diels as its head. Göring, concerned that Diels was not ruthless enough to use the Gestapo effectively to counteract the power of the SA, handed over its control to Himmler on 20 April 1934. Also on that date, Hitler appointed Himmler chief of all German police outside Prussia. This was a radical departure from long-standing German practice that law enforcement was a state and local matter. Heydrich, named chief of the Gestapo by Himmler on 22 April 1934, also continued as head of the SD.

Hitler decided on 21 June that Röhm and the SA leadership had to be eliminated. He sent Göring to Berlin on 29 June, to meet with Himmler and Heydrich to plan the action. Hitler took charge in Munich, where Röhm was arrested; he gave Röhm the choice to commit suicide or be shot. When Röhm refused to kill himself, he was shot dead by two SS officers. Between 85 and 200 members of the SA leadership and other political adversaries, including Gregor Strasser, were killed between 30 June and 2 July 1934 in these actions, known as the Night of the Long Knives. With the SA thus neutralised, the SS became an independent organisation answerable only to Hitler on 20 July 1934. Himmler's title of Reichsführer-SS became the highest formal SS rank, equivalent to a field marshal in the army. The SA was converted into a sports and training organisation.

On 15 September 1935, Hitler presented two laws—known as the Nuremberg Laws—to the Reichstag. The laws banned marriage between non-Jewish and Jewish Germans and forbade the employment of non-Jewish women under the age of 45 in Jewish households. The laws also deprived so-called "non-Aryans" of the benefits of German citizenship. These laws were among the first race-based measures instituted by the Third Reich.

Himmler and Heydrich wanted to extend the power of the SS; thus, they urged Hitler to form a national police force overseen by the SS, to guard Nazi Germany against its many enemies at the time—real and imagined. Interior Minister Frick also wanted a national police force, but one controlled by him, with Kurt Daluege as his police chief. Hitler left it to Himmler and Heydrich to work out the arrangements with Frick. Himmler and Heydrich had greater bargaining power, as they were allied with Frick's old enemy, Göring. Heydrich drew up a set of proposals and Himmler sent him to meet with Frick. An angry Frick then consulted with Hitler, who told him to agree to the proposals. Frick acquiesced, and on 17 June 1936 Hitler decreed the unification of all police forces in the Reich and named Himmler Chief of German Police and a State Secretary in the Ministry of the Interior. In this role, Himmler was still nominally subordinate to Frick. In practice, however, the police were now effectively a division of the SS, and hence independent of Frick's control. This move gave Himmler operational control over Germany's entire detective force. He also gained authority over all of Germany's uniformed law enforcement agencies, which were amalgamated into the new Ordnungspolizei (Orpo: "order police"), which became a branch of the SS under Daluege.

Shortly thereafter, Himmler created the Kriminalpolizei (Kripo: criminal police) as an umbrella organisation for all criminal investigation agencies in Germany. The Kripo was merged with the Gestapo into the Sicherheitspolizei (SiPo: security police), under Heydrich's command. In September 1939, following the outbreak of World War II, Himmler formed the SS-Reichssicherheitshauptamt (RSHA: Reich Security Main Office) to bring the SiPo (which included the Gestapo and Kripo) and the SD together under one umbrella. He again placed Heydrich in command.

Under Himmler's leadership, the SS developed its own military branch, the SS-Verfügungstruppe (SS-VT), which later evolved into the Waffen-SS. Nominally under the authority of Himmler, the Waffen-SS developed a fully militarised structure of command and operations. It grew from three regiments to over 38 divisions during World War II, serving alongside the Heer (army), but never being formally part of it.

In addition to his military ambitions, Himmler established the beginnings of a parallel economy under the umbrella of the SS. To this end, administrator Oswald Pohl set up the Deutsche Wirtschaftsbetriebe (German Economic Enterprise) in 1940. Under the auspices of the SS Economy and Administration Head Office, this holding company owned housing corporations, factories, and publishing houses. Pohl was unscrupulous and quickly exploited the companies for personal gain. In contrast, Himmler was honest in matters of money and business.

In 1938, as part of his preparations for war, Hitler ended the German alliance with China and entered into an agreement with the more modern Japan. That same year, Austria was unified with Nazi Germany in the Anschluss, and the Munich Agreement gave Nazi Germany control over the Sudetenland, part of Czechoslovakia. Hitler's primary motivations for war included obtaining additional Lebensraum ("living space") for the Germanic peoples, who were considered racially superior according to Nazi ideology. A second goal was the elimination of those considered racially inferior, particularly the Jews and Slavs, from territories controlled by the Reich. From 1933 to 1938, hundreds of thousands of Jews emigrated to the United States, Palestine, Great Britain, and other countries. Some converted to Christianity.

Anti-church struggle
According to Himmler biographer Peter Longerich, Himmler believed that a major task of the SS should be "acting as the vanguard in overcoming Christianity and restoring a 'Germanic' way of living" as part of preparations for the coming conflict between "humans and subhumans". Longerich wrote that, while the Nazi movement as a whole launched itself against Jews and Communists, "by linking de-Christianisation with re-Germanization, Himmler had provided the SS with a goal and purpose all of its own". Himmler was vehemently opposed to Christian sexual morality and the "principle of Christian mercy", both of which he saw as dangerous obstacles to his planned battle with "subhumans". In 1937, Himmler declared:

"We live in an era of the ultimate conflict with Christianity. It is part of the mission of the SS to give the German people in the next half century the non-Christian ideological foundations on which to lead and shape their lives. This task does not consist solely in overcoming an ideological opponent but must be accompanied at every step by a positive impetus: in this case that means the reconstruction of the German heritage in the widest and most comprehensive sense."

In early 1937, Himmler had his personal staff work with academics to create a framework to replace Christianity within the Germanic cultural heritage. The project gave rise to the Deutschrechtliches Institut, headed by Professor Karl Eckhardt, at the University of Bonn.

World War II
When Hitler and his army chiefs asked for a pretext for the invasion of Poland in 1939, Himmler, Heydrich, and Heinrich Müller masterminded and carried out a false flag project code-named Operation Himmler. German soldiers dressed in Polish uniforms undertook border skirmishes which deceptively suggested Polish aggression against Germany. The incidents were then used in Nazi propaganda to justify the invasion of Poland, the opening event of World War II. At the beginning of the war against Poland, Hitler authorised the killing of Polish civilians, including Jews and ethnic Poles. The Einsatzgruppen (SS task forces) had originally been formed by Heydrich to secure government papers and offices in areas taken over by Germany before World War II. Authorised by Hitler and under the direction of Himmler and Heydrich, the Einsatzgruppen units—now repurposed as death squads—followed the Heer (army) into Poland, and by the end of 1939 they had murdered some 65,000 intellectuals and other civilians. Militias and Heer units also took part in these killings. Under Himmler's orders via the RSHA, these squads were also tasked with rounding up Jews and others for placement in ghettos and concentration camps.

Germany subsequently invaded Denmark and Norway, the Netherlands, and France, and began bombing Great Britain in preparation for Operation Sea Lion, the planned invasion of the United Kingdom. On 21 June 1941, the day before invasion of the Soviet Union, Himmler commissioned the preparation of the Generalplan Ost (General Plan for the East); the plan was approved by Hitler in May 1942. It called for the Baltic States, Poland, Western Ukraine, and Byelorussia to be conquered and resettled by ten million German citizens. The current residents—some 31 million people—would be expelled further east, starved, or used for forced labour. The plan would have extended the borders of Germany to the east by 1000 km. Himmler expected that it would take twenty to thirty years to complete the plan, at a cost of. Himmler stated openly: "It is a question of existence, thus it will be a racial struggle of pitiless severity, in the course of which 20 to 30 million Slavs and Jews will perish through military actions and crises of food supply."

Himmler declared that the war in the east was a pan-European crusade to defend the traditional values of old Europe from the "Godless Bolshevik hordes". Constantly struggling with the Wehrmacht for recruits, Himmler solved this problem through the creation of Waffen-SS units composed of Germanic folk groups taken from the Balkans and eastern Europe. Equally vital were recruits from among the Germanic considered peoples of northern and western Europe, in the Netherlands, Norway, Belgium, Denmark and Finland. Spain and Italy also provided men for Waffen-SS units. Among western countries, the number of volunteers varied from a high of 25,000 from the Netherlands to 300 each from Sweden and Switzerland. From the east, the highest number of men came from Lithuania (50,000) and the lowest from Bulgaria (600). After 1943 most men from the east were conscripts. The performance of the eastern Waffen-SS units was, as a whole, sub-standard.

In late 1941, Hitler named Heydrich as Deputy Reich Protector of the newly established Protectorate of Bohemia and Moravia. Heydrich began to racially classify the Czechs, deporting many to concentration camps. Members of a swelling resistance were shot, earning Heydrich the nickname "the Butcher of Prague". This appointment strengthened the collaboration between Himmler and Heydrich, and Himmler was proud to have SS control over a state. Despite having direct access to Hitler, Heydrich's loyalty to Himmler remained firm.

With Hitler's approval, Himmler re-established the Einsatzgruppen in the lead-up to the planned invasion of the Soviet Union. In March 1941, Hitler addressed his army leaders, detailing his intention to smash the Soviet Empire and destroy the Bolshevik intelligentsia and leadership. His special directive, the "Guidelines in Special Spheres re Directive No. 21 (Operation Barbarossa)", read: "In the operations area of the army, the Reichsführer-SS has been given special tasks on the orders of the Führer, in order to prepare the political administration. These tasks arise from the forthcoming final struggle of two opposing political systems. Within the framework of these tasks, the Reichsführer-SS acts independently and on his own responsibility." Hitler thus intended to prevent internal friction like that occurring earlier in Poland in 1939, when several German Army generals (including Johannes Blaskowitz) had attempted to bring Einsatzgruppen leaders to trial for the murders they had committed.

Following the army into the Soviet Union, the Einsatzgruppen rounded up and killed Jews and others deemed undesirable by the Nazi state. Hitler was sent frequent reports. In addition, 2.8 million Soviet prisoners of war died of starvation, mistreatment or executions in just eight months of 1941–42. As many as 500,000 Soviet prisoners of war died or were executed in Nazi concentration camps over the course of the war; most of them were shot or gassed. By early 1941, following Himmler's orders, ten concentration camps had been constructed in which inmates were subjected to forced labour. Jews from all over Germany and the occupied territories were deported to the camps or confined to ghettos. As the Germans were pushed back from Moscow in December 1941, signalling that the expected quick defeat of the Soviet Union had failed to materialize, Hitler and other Nazi officials realised that mass deportations to the east would no longer be possible. As a result, instead of deportation, many Jews in Europe were destined for death.

Final Solution, the Holocaust, racial policy, and eugenics

Nazi racial policies, including the notion that people who were racially inferior had no right to live, date back to the earliest days of the party; Hitler discusses this in Mein Kampf. Around the time of the German declaration of war on the United States in December 1941, Hitler resolved that the Jews of Europe were to be "exterminated". Heydrich arranged a meeting, held on 20 January 1942 at Wannsee, a suburb of Berlin. Attended by top Nazi officials, it was used to outline the plans for the "final solution to the Jewish question". Heydrich detailed how those Jews able to work would be worked to death; those unable to work would be killed outright. Heydrich calculated the number of Jews to be killed at 11 million and told the attendees that Hitler had placed Himmler in charge of the plan.

In June 1942, Heydrich was assassinated in Prague in Operation Anthropoid, led by Jozef Gabčík and Jan Kubiš, members of Czechoslovakia's army-in-exile. Both men had been trained by the British Special Operations Executive for the mission to kill Heydrich. During the two funeral services, Himmler—the chief mourner—took charge of Heydrich's two young sons, and he gave the eulogy in Berlin. On 9 June, after discussions with Himmler and Karl Hermann Frank, Hitler ordered brutal reprisals for Heydrich's death. Over 13,000 people were arrested, and the village of Lidice was razed to the ground; its male inhabitants and all adults in the village of Ležáky were murdered. At least 1,300 people were executed by firing squads. Himmler took over leadership of the RSHA and stepped up the pace of the killing of Jews in Aktion Reinhard (Operation Reinhard), named in Heydrich's honour. He ordered the Aktion Reinhard camps—three extermination camps—to be constructed at Bełżec, Sobibór, and Treblinka.

Initially the victims were killed with gas vans or by firing squad, but these methods proved impracticable for an operation of this scale. In August 1941, Himmler attended the shooting of 100 Jews at Minsk. A "military virgin" this was the first time he heard a shot fired in anger or seen dead people, and in Minsk while looking into the open grave his coat and perhaps his face were splashed by the brains of a victim. He went very green and pale and swayed. Karl Wolff jumped forward, held him steady and led him away from the grave. Nauseated and shaken by the experience, he was concerned about the impact such actions would have on the mental health of his SS men.

He decided that alternate methods of killing should be found. On his orders, by early 1942 the camp at Auschwitz had been greatly expanded, including the addition of gas chambers, where victims were killed using the pesticide Zyklon B. Himmler visited the camp in person on 17 and 18 July 1942. He was given a demonstration of a mass killing using the gas chamber in Bunker 2 and toured the building site of the new IG Farben plant being constructed at the nearby town of Monowitz. By the end of the war, at least 5.5 million Jews had been killed by the Nazi regime; most estimates range closer to 6 million. Himmler visited the camp at Sobibór in early 1943, by which time 250,000 people had been killed at that location alone. After witnessing a gassing, he gave 28 people promotions and ordered the operation of the camp to be wound down. In a prisoner revolt that October, the remaining prisoners killed most of the guards and SS personnel. Several hundred prisoners escaped; about a hundred were immediately re-captured and killed. Some of the escapees joined partisan units operating in the area. The camp was dismantled by December 1943.

The Nazis also targeted Romani (Gypsies) as "asocial" and "criminals". By 1935, they were confined into special camps away from ethnic Germans. In 1938, Himmler issued an order in which he said that the "Gypsy question" would be determined by "race". Himmler believed that the Romani were originally Aryan but had become a mixed race; only the "racially pure" were to be allowed to live. In 1939, Himmler ordered thousands of Gypsies to be sent to the Dachau concentration camp and by 1942, ordered all Romani sent to Auschwitz concentration camp.

Himmler was one of the main architects of the Holocaust, using his deep belief in the racist Nazi ideology to justify the murder of millions of victims. Longerich surmises that Hitler, Himmler, and Heydrich designed the Holocaust during a period of intensive meetings and exchanges in April–May 1942. The Nazis planned to kill Polish intellectuals and restrict non-Germans in the General Government and conquered territories to a fourth-grade education. They further wanted to breed a master race of racially pure Nordic Aryans in Germany. As a student of agriculture and a farmer, Himmler was acquainted with the principles of selective breeding, which he proposed to apply to humans. He believed that he could engineer the German populace, for example, through eugenics, to be Nordic in appearance within several decades of the end of the war.

Posen speeches
On 4 October 1943, during a secret meeting with top SS officials in the city of Poznań (Posen), and on 6 October 1943, in a speech to the party elite—the Gauleiters and Reichsleiters—Himmler referred explicitly to the "extermination" (Ausrottung) of the Jewish people.

A translated excerpt from the speech of 4 October reads: "I also want to refer here very frankly to a very difficult matter. We can now very openly talk about this among ourselves, and yet we will never discuss this publicly. Just as we did not hesitate on 30 June 1934, to perform our duty as ordered and put comrades who had failed up against the wall and execute them, we also never spoke about it, nor will we ever speak about it. Let us thank God that we had within us enough self-evident fortitude never to discuss it among us, and we never talked about it. Every one of us was horrified, and yet every one clearly understood that we would do it next time, when the order is given and when it becomes necessary.

I am talking about the 'Jewish evacuation': the extermination of the Jewish people. It is one of those things that is easily said. 'The Jewish people is being exterminated', every Party member will tell you, 'perfectly clear, it's part of our plans, we're eliminating the Jews, exterminating them, ha!, a small matter.' And then they turn up, the upstanding 80 million Germans, and each one has his decent Jew. They say the others are all swines, but this particular one is a splendid Jew. But none has observed it, endured it. Most of you here know what it means when 100 corpses lie next to each other, when there are 500 or when there are 1,000. To have endured this and at the same time to have remained a decent person—with exceptions due to human weaknesses—has made us tough, and is a glorious chapter that has not and will not be spoken of. Because we know how difficult it would be for us if we still had Jews as secret saboteurs, agitators and rabble-rousers in every city, what with the bombings, with the burden and with the hardships of the war. If the Jews were still part of the German nation, we would most likely arrive now at the state we were at in 1916 and '17 ..."

Because the Allies had indicated that they were going to pursue criminal charges for German war crimes, Hitler tried to gain the loyalty and silence of his subordinates by making them all parties to the ongoing genocide. Hitler therefore authorised Himmler's speeches to ensure that all party leaders were complicit in the crimes and could not later deny knowledge of the killings.

Germanization policies and Generalplan Ost
As Reich Commissioner for the Consolidation of German Nationhood (RKFDV) with the incorporated VoMi, Himmler was deeply involved in the Germanization program for the East, particularly Poland. As laid out in Generalplan Ost, the aim was to enslave, expel or exterminate the native population and to make Lebensraum ("living space") for Volksdeutsche (ethnic Germans). He continued his plans to colonise the east, even when many Germans were reluctant to relocate there, and despite negative effects on the war effort. Approximately 11 million Slavic and 3.4 million Jewish inhabitants of Eastern Europe were killed in Nazi Germany's extermination campaigns during the implementation of Generalplan Ost.

Himmler's racial groupings began with the Volksliste, the classification of people deemed of German blood. These included Germans who had collaborated with Germany before the war, but also those who considered themselves German but had been neutral; those who were partially "Polonized" but "Germanizable"; and Germans who were of Polish nationality. Himmler ordered that those who refused to be classified as ethnic Germans should be deported to concentration camps, have their children taken away, or be assigned to forced labour. Himmler's belief that "it is in the nature of German blood to resist" led to his conclusion that Balts or Slavs who resisted Germanization were racially superior to more compliant ones. He declared that no drop of German blood would be lost or left behind to mingle with an "alien race".

The plan also included the kidnapping of Eastern European children by Nazi Germany. Himmler urged: "Obviously in such a mixture of peoples, there will always be some racially good types. Therefore, I think that it is our duty to take their children with us, to remove them from their environment, if necessary by robbing, or stealing them. Either we win over any good blood that we can use for ourselves and give it a place in our people, ... or we destroy that blood."

The "racially valuable" children were to be removed from all contact with Poles and raised as Germans, with German names. Himmler declared: "We have faith above all in this our own blood, which has flowed into a foreign nationality through the vicissitudes of German history. We are convinced that our own philosophy and ideals will reverberate in the spirit of these children who racially belong to us." The children were to be adopted by German families. Children who passed muster at first but were later rejected were taken to Kinder KZ in Łódź Ghetto, where most of them eventually died.

By January 1943, Himmler reported that 629,000 ethnic Germans had been resettled; however, most resettled Germans did not live in the envisioned small farms, but in temporary camps or quarters in towns. Half a million residents of the annexed Polish territories, as well as from Slovenia, Alsace, Lorraine, and Luxembourg were deported to the General Government or sent to Germany as slave labour. Himmler instructed that the German nation should view all foreign workers brought to Germany as a danger to their German blood. In accordance with German racial laws, sexual relations between Germans and foreigners were forbidden as Rassenschande (race defilement).

20 July plot
On 20 July 1944, a group of German army officers led by Claus von Stauffenberg and including some of the highest-ranked members of the German armed forces attempted to assassinate Hitler, but failed to do so. The next day, Himmler formed a special commission that arrested over 5,000 suspected and known opponents of the regime. Hitler ordered brutal reprisals that resulted in the execution of more than 4,900 people. Though Himmler was embarrassed by his failure to uncover the plot, it led to an increase in his powers and authority.

General Friedrich Fromm, commander-in-chief of the Replacement Army (Ersatzheer) and Stauffenberg's immediate superior, was one of those implicated in the conspiracy. Hitler removed Fromm from his post and named Himmler as his successor. Since the Replacement Army consisted of two million men, Himmler hoped to draw on these reserves to fill posts within the Waffen-SS. He appointed Hans Jüttner, director of the SS Leadership Main Office, as his deputy, and began to fill top Replacement Army posts with SS men. By November 1944, Himmler had merged the army officer recruitment department with that of the Waffen-SS and had successfully lobbied for an increase in the quotas for recruits to the SS.

By this time, Hitler had appointed Himmler as Reichsminister of the Interior, succeeding Frick, and General Plenipotentiary for Administration (Generalbevollmächtigter für die Verwaltung). At the same time (24 August 1943) he also joined the six-member Council of Ministers for the Defense of the Reich, which operated as the war cabinet. In August 1944 Hitler authorised him to restructure the organisation and administration of the Waffen-SS, the army, and the police services. As head of the Replacement Army, Himmler was now responsible for prisoners of war. He was also in charge of the Wehrmacht penal system, and controlled the development of Wehrmacht armaments until January 1945.

Command of army group
On 6 June 1944, the Western Allied armies landed in northern France during Operation Overlord. In response, Army Group Upper Rhine (Heeresgruppe Oberrhein) group was formed to engage the advancing US 7th Army (under command of General Alexander Patch) and French 1st Army (led by General Jean de Lattre de Tassigny) in the Alsace region along the west bank of the Rhine. In late 1944, Hitler appointed Himmler commander-in-chief of Army Group Upper Rhine.

On 26 September 1944, Hitler ordered Himmler to create special army units, the Volkssturm ("People's Storm" or "People's Army"). All males aged sixteen to sixty were eligible for conscription into this militia, over the protests of Armaments Minister Albert Speer, who noted that irreplaceable skilled workers were being removed from armaments production. Hitler confidently believed six million men could be raised, and the new units would "initiate a people's war against the invader". These hopes were wildly optimistic. In October 1944, children as young as fourteen were being enlisted. Because of severe shortages in weapons and equipment and lack of training, members of the Volkssturm were poorly prepared for combat, and about 175,000 of them died in the final months of the war.

On 1 January 1945, Hitler and his generals launched Operation North Wind. The goal was to break through the lines of the US 7th Army and French 1st Army to support the southern thrust in the Battle of the Bulge (Ardennes offensive), the final major German offensive of the war. After limited initial gains by the Germans, the Americans halted the offensive. By 25 January, Operation North Wind had officially ended.

On 25 January 1945, despite Himmler's lack of military experience, Hitler appointed him as commander of the hastily formed Army Group Vistula (Heeresgruppe Weichsel) to halt the Soviet Red Army's Vistula–Oder offensive into Pomerania – a decision that appalled the German General Staff. Himmler established his command centre at Schneidemühl, using his special train, Sonderzug Steiermark, as his headquarters. The train had only one telephone line, inadequate maps, and no signal detachment or radios with which to establish communication and relay military orders. Himmler seldom left the train, only worked about four hours per day, and insisted on a daily massage before commencing work and a lengthy nap after lunch.

General Heinz Guderian talked to Himmler on 9 February and demanded that Operation Solstice, an attack from Pomerania against the northern flank of Marshal Georgy Zhukov's 1st Belorussian Front, should be in progress by the 16th. Himmler argued that he was not ready to commit himself to a specific date. Given Himmler's lack of qualifications as an army group commander, Guderian convinced himself that Himmler tried to conceal his incompetence. On 13 February Guderian met Hitler and demanded that General Walther Wenck be given a special mandate to command the offensive by Army Group Vistula. Hitler sent Wenck with a "special mandate", but without specifying Wenck's authority. The offensive was launched on 16 February 1945, but soon stuck in rain and mud, facing mine fields and strong antitank defenses. That night Wenck was severely injured in a car accident, but it is doubtful that he could have salvaged the operation, as Guderian later claimed. Himmler ordered the offensive to stop on the 18th by a "directive for regrouping". Hitler officially ended Operation Solstice on 21 February and ordered Himmler to transfer a corps headquarter and three divisions to Army Group Center.

Himmler was unable to devise any viable plans for completion of his military objectives. Under pressure from Hitler over the worsening military situation, Himmler became anxious and unable to give him coherent reports. When the counter-attack failed to stop the Soviet advance, Hitler held Himmler personally liable and accused him of not following orders. Himmler's military command ended on 20 March, when Hitler replaced him with General Gotthard Heinrici as Commander-in-Chief of Army Group Vistula. By this time Himmler, who had been under the care of his doctor since 18 February, had fled to the Hohenlychen Sanatorium. Hitler sent Guderian on a forced medical leave of absence, and he reassigned his post as chief of staff to Hans Krebs on 29 March. Himmler's failure and Hitler's response marked a serious deterioration in the relationship between the two men. By that time, the inner circle of people whom Hitler trusted was rapidly shrinking.

Peace negotiations
In early 1945, the German war effort was on the verge of collapse and Himmler's relationship with Hitler had deteriorated. Himmler considered independently negotiating a peace settlement. His masseur, Felix Kersten, who had moved to Sweden, acted as an intermediary in negotiations with Count Folke Bernadotte, head of the Swedish Red Cross. Letters were exchanged between the two men, and direct meetings were arranged by Walter Schellenberg of the RSHA.

In March 1945, Himmler issued a directive that Jews were to be marched from the South-east wall (Südostwall) fortifications construction project on the Austro-Hungarian border, to Mauthausen. He desired hostages for potential peace negotiations. Thousands died on the marches.

Himmler and Hitler met for the last time on 20 April 1945—Hitler's birthday—in Berlin, and Himmler swore unswerving loyalty to Hitler. At a military briefing on that day, Hitler stated that he would not leave Berlin, in spite of Soviet advances. Along with Göring, Himmler quickly left the city after the briefing. On 21 April, Himmler met with Norbert Masur, a Swedish representative of the World Jewish Congress, to discuss the release of Jewish concentration camp inmates. As a result of these negotiations, about 20,000 people were released in the White Buses operation. Himmler falsely claimed in the meeting that the crematoria at camps had been built to deal with the bodies of prisoners who had died in a typhus epidemic. He also claimed very high survival rates for the camps at Auschwitz and Bergen-Belsen, even as these sites were liberated and it became obvious that his figures were false.

On 23 April, Himmler met directly with Bernadotte at the Swedish consulate in Lübeck. Representing himself as the provisional leader of Germany, he claimed that Hitler would be dead within the next few days. Hoping that the British and Americans would fight the Soviets alongside what remained of the Wehrmacht, Himmler asked Bernadotte to inform General Dwight Eisenhower that Germany wished to surrender to the Western Allies, and not to the Soviet Union. Bernadotte asked Himmler to put his proposal in writing, and Himmler obliged.

Meanwhile, Göring had sent a telegram, a few hours earlier, asking Hitler for permission to assume leadership of the Reich in his capacity as Hitler's designated deputy—an act that Hitler, under the prodding of Martin Bormann, interpreted as a demand to step down or face a coup. On 27 April, Himmler's SS representative at Hitler's HQ in Berlin, Hermann Fegelein, was caught in civilian clothes preparing to desert; he was arrested and brought back to the Führerbunker. On the evening of 28 April, the BBC broadcast a Reuters news report about Himmler's attempted negotiations with the western Allies. Hitler had long considered Himmler to be second only to Joseph Goebbels in loyalty; he called Himmler "the loyal Heinrich" (der treue Heinrich). Hitler flew into a rage at this betrayal, and told those still with him in the bunker complex that Himmler's secret negotiations were the worst treachery he had ever known. Hitler ordered Himmler's arrest, and Fegelein was court-martialed and shot.

By this time, the Soviets had advanced to the Potsdamer Platz, only 300 m from the Reich Chancellery, and were preparing to storm the Chancellery. This report, combined with Himmler's treachery, prompted Hitler to write his last will and testament. In the testament, completed on 29 April—one day prior to his suicide—Hitler declared both Himmler and Göring to be traitors. He stripped Himmler of all of his party and state offices and expelled him from the Nazi Party.

Hitler named Grand Admiral Karl Dönitz as his successor. Himmler met Dönitz in Flensburg and offered himself as second-in-command. He maintained that he was entitled to a position in Dönitz's interim government as Reichsführer-SS, believing the SS would be in a good position to restore and maintain order after the war. Dönitz repeatedly rejected Himmler's overtures and initiated peace negotiations with the Allies. He wrote a letter on 6 May—two days before the German Instrument of Surrender—formally dismissing Himmler from all his posts.

Capture and death

Rejected by his former comrades and hunted by the Allies, Himmler attempted to go into hiding. He had not made extensive preparations for this, but he carried a forged paybook under the name of Sergeant Heinrich Hizinger. On 11 May 1945, with a small band of companions, he headed south to Friedrichskoog, without a final destination in mind. They continued on to Neuhaus, where the group split up. On 21 May, Himmler and two aides were stopped and detained at a checkpoint in Bremervörde set up by former Soviet POWs. Over the following two days, he was moved around to several camps and was brought to the British 31st Civilian Interrogation Camp near Lüneburg, on 23 May. The officials noticed that Himmler's identity papers bore a stamp which British military intelligence had seen being used by fleeing members of the SS.

The duty officer, Captain Thomas Selvester, began a routine interrogation. Himmler admitted who he was, and Selvester had the prisoner searched. Himmler was taken to the headquarters of the Second British Army in Lüneburg, where a doctor conducted a medical exam on him. The doctor attempted to examine the inside of Himmler's mouth, but the prisoner was reluctant to open it and jerked his head away. Himmler then bit into a hidden potassium cyanide pill and collapsed onto the floor. He was dead within 15 minutes, despite efforts to expel the poison from his system. Shortly afterward, Himmler's body was buried in an unmarked grave near Lüneburg. The grave's location remains unknown.

Mysticism and symbolism

Himmler was interested in mysticism and the occult from an early age. He tied this interest into his racist philosophy, looking for proof of Aryan and Nordic racial superiority from ancient times. He promoted a cult of ancestor worship, particularly among members of the SS, as a way to keep the race pure and provide immortality to the nation. Viewing the SS as an "order" along the lines of the Teutonic Knights, he had them take over the Church of the Teutonic Order in Vienna in 1939. He began the process of replacing Christianity with a new moral code that rejected humanitarianism and challenged the Christian concept of marriage. The Ahnenerbe, a research society founded by Himmler in 1935, searched the globe for proof of the superiority and ancient origins of the Germanic race.

All regalia and uniforms of Nazi Germany, particularly those of the SS, used symbolism in their designs. The stylised lightning bolt logo of the SS was chosen in 1932. The logo is a pair of runes from a set of 18 Armanen runes created by Guido von List in 1906. The ancient Sowilō rune originally symbolised the sun, but was renamed "Sieg" (victory) in List's iconography. Himmler modified a variety of existing customs to emphasise the elitism and central role of the SS; an SS naming ceremony was to replace baptism, marriage ceremonies were to be altered, a separate SS funeral ceremony was to be held in addition to Christian ceremonies, and SS-centric celebrations of the summer and winter solstices were instituted. The Totenkopf (death's head) symbol, used by German military units for hundreds of years, had been chosen for the SS by Julius Schreck. Himmler placed particular importance on the death's-head rings; they were never to be sold, and were to be returned to him upon the death of the owner. He interpreted the death's-head symbol to mean solidarity to the cause and a commitment unto death.

Relationship with Hitler
As second in command of the SS and then Reichsführer-SS, Himmler was in regular contact with Hitler to arrange for SS men as bodyguards; Himmler was not involved with Nazi Party policy-making decisions in the years leading up to the seizure of power. From the late 1930s, the SS was independent of the control of other state agencies or government departments, and he reported only to Hitler.

Hitler promoted and practised the Führerprinzip. The principle required absolute obedience of all subordinates to their superiors; thus Hitler viewed the government structure as a pyramid, with himself—the infallible leader—at the apex. Accordingly, Himmler placed himself in a position of subservience to Hitler, and was unconditionally obedient to him. However, he—like other top Nazi officials—had aspirations to one day succeed Hitler as leader of the Reich. Himmler considered Speer to be an especially dangerous rival, both in the Reich administration and as a potential successor to Hitler.

Hitler called Himmler's mystical and pseudoreligious interests "nonsense". Himmler was not a member of Hitler's inner circle; the two men were not very close, and rarely saw each other socially. Himmler socialised almost exclusively with other members of the SS. His unconditional loyalty and efforts to please Hitler earned him the nickname of der treue Heinrich ("the faithful Heinrich"). However, in the last days of the war, when it became clear that Hitler planned to die in Berlin, Himmler left his long-time superior to try to save himself.

Marriage and family

Himmler met his future wife, Margarete Boden, in 1927. Seven years his senior, she was a nurse who shared his interest in herbal medicine and homoeopathy, and was part owner of a small private clinic. They were married in July 1928, and their only child, Gudrun, was born on 8 August 1929. The couple were also foster parents to a boy named Gerhard von Ahe, son of an SS officer who had died before the war. Margarete sold her share of the clinic and used the proceeds to buy a plot of land in Waldtrudering, near Munich, where they erected a prefabricated house. Himmler was constantly away on party business, so his wife took charge of their efforts—mostly unsuccessful—to raise livestock for sale. They had a dog, Töhle.

After the Nazis came to power the family moved first to Möhlstrasse in Munich, and in 1934 to Tegernsee, where they bought a house. Himmler also later obtained a large house in the Berlin suburb of Dahlem, free of charge, as an official residence. The couple saw little of each other as Himmler became totally absorbed by work. The relationship was strained. The couple did unite for social functions; they were frequent guests at the Heydrich home. Margarete saw it as her duty to invite the wives of the senior SS leaders over for afternoon coffee and tea on Wednesday afternoons.

Hedwig Potthast, Himmler's young secretary starting in 1936, became his mistress by 1939. She left her job in 1941. He arranged accommodation for her, first in Mecklenburg and later at Berchtesgaden. He fathered two children with her: a son, Helge (born 15 February 1942, Mecklenburg) and a daughter, Nanette Dorothea (born 20 July 1944, Berchtesgaden). Margarete, by then living in Gmund with her daughter, learned of the relationship sometime in 1941; she and Himmler were already separated, and she decided to tolerate the relationship for the sake of her daughter. Working as a nurse for the German Red Cross during the war, Margarete was appointed supervisor in one of Germany's military districts, Wehrkreis III (Berlin-Brandenburg). Himmler was close to his first daughter, Gudrun, whom he nicknamed Püppi ("dolly"); he phoned her every few days and visited as often as he could.

Margarete's diaries record that Gerhard left the National Political Educational Institute in Berlin due to poor examination results. At 16 he joined the SS in Brno and fought on the Eastern Front. He was captured by the Russians but was later returned to Germany.

Hedwig and Margarete both remained loyal to Himmler. Writing to Gebhard in February 1945, Margarete said, "How wonderful that he has been called to great tasks and is equal to them. The whole of Germany is looking to him." Hedwig expressed similar sentiments in a letter to Himmler in January. Margarete and Gudrun left Gmund as Allied troops advanced into the area. They were arrested by American troops in Bolzano, Italy, and held in various internment camps in Italy, France, and Germany. They were brought to Nuremberg to testify at the trials and were released in November 1946. Gudrun emerged from the experience embittered by her alleged mistreatment and remained devoted to her father's memory. She later worked for the West German spy agency Bundesnachrichtendienst (BND) from 1961 to 1963.

Historical assessment
Peter Longerich observes that Himmler's ability to consolidate his ever-increasing powers and responsibilities into a coherent system under the auspices of the SS led him to become one of the most powerful men in the Third Reich. Historian Wolfgang Sauer says that "although he was pedantic, dogmatic, and dull, Himmler emerged under Hitler as second in actual power. His strength lay in a combination of unusual shrewdness, burning ambition, and servile loyalty to Hitler." In 2008, the German news magazine Der Spiegel described Himmler as one of the most brutal mass murderers in history and the architect of the Holocaust.

Historian John Toland relates a story by Günter Syrup, a subordinate of Heydrich. Heydrich showed him a picture of Himmler and said: "The top half is the teacher, but the lower half is the sadist." Historian Adrian Weale comments that Himmler and the SS followed Hitler's policies without question or ethical considerations. Himmler accepted Hitler and Nazi ideology and saw the SS as a chivalric Teutonic order of new Germans. Himmler adopted the doctrine of Auftragstaktik ("mission command"), whereby orders were given as broad directives, with authority delegated downward to the appropriate level to carry them out in a timely and efficient manner. Weale states that the SS ideology gave the men a doctrinal framework, and the mission command tactics allowed the junior officers leeway to act on their own initiative to obtain the desired results.

title: Heinrich Himmler


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HTTP

HTTP (Hypertext Transfer Protocol) is an application layer protocol in the Internet protocol suite model for distributed, collaborative, hypermedia information systems. HTTP is the foundation of data communication for the World Wide Web, where hypertext documents include hyperlinks to other resources that the user can easily access, for example by a mouse click or by tapping the screen in a web browser.

Development of HTTP was initiated by Tim Berners-Lee at CERN in 1989 and summarized in a simple document describing the behavior of a client and a server using the first HTTP version, named 0.9. That version was subsequently developed, eventually becoming the public 1.0.

Development of early HTTP Requests for Comments (RFCs) started a few years later in a coordinated effort by the Internet Engineering Task Force (IETF) and the World Wide Web Consortium (W3C), with work later moving to the IETF.

HTTP/1 was finalized and fully documented (as version 1.0) in 1996. It evolved (as version 1.1) in 1997 and then its specifications were updated in 1999, 2014, and 2022.

Its secure variant named HTTPS is used by more than 85% of websites. HTTP/2, published in 2015, provides a more efficient expression of HTTP's semantics "on the wire". it is used by 36% of websites and supported by almost all web browsers (over 98% of users). It is also supported by major web servers over Transport Layer Security (TLS) using an Application-Layer Protocol Negotiation (ALPN) extension where TLS 1.2 or newer is required.

HTTP/3, the successor to HTTP/2, was published in 2022. it is now used on 29% of websites and is supported by most web browsers, i.e. (at least partially) supported by 97% of users. HTTP/3 uses QUIC instead of TCP for the underlying transport protocol. Like HTTP/2, it does not obsolesce previous major versions of the protocol. Support for HTTP/3 was added to Cloudflare and Google Chrome first, and is also enabled in Firefox. HTTP/3 has lower latency for real-world web pages, if enabled on the server, and loads faster than with HTTP/2, in some cases over three times faster than HTTP/1.1 (which is still commonly only enabled).

Technical overview
HTTP functions as a request–response protocol in the client–server model. A web browser, for example, may be the client whereas a process, named web server, running on a computer hosting one or more websites may be the server. The client submits an HTTP request message to the server. The server, which provides resources such as HTML files and other content or performs other functions on behalf of the client, returns a response message to the client. The response contains completion status information about the request and may also contain requested content in its message body.

A web browser is an example of a user agent (UA). Other types of user agent include the indexing software used by search providers (web crawlers), voice browsers, mobile apps, and other software that accesses, consumes, or displays web content.

HTTP is designed to permit intermediate network elements to improve or enable communications between clients and servers. High-traffic websites often benefit from web cache servers that deliver content on behalf of upstream servers to improve response time. Web browsers cache previously accessed web resources and reuse them, whenever possible, to reduce network traffic. HTTP proxy servers at private network boundaries can facilitate communication for clients without a globally routable address, by relaying messages with external servers.

To allow intermediate HTTP nodes (proxy servers, web caches, etc.) to accomplish their functions, some of the HTTP headers (found in HTTP requests/responses) are managed hop-by-hop whereas other HTTP headers are managed end-to-end (managed only by the source client and by the target web server).

HTTP is an application layer protocol designed within the framework of the Internet protocol suite. Its definition presumes an underlying and reliable transport layer protocol. In the latest version HTTP/3, the Transmission Control Protocol (TCP) is no longer used, but the older versions are still more used and they most commonly use TCP. They have also been adapted to use unreliable protocols such as the User Datagram Protocol (UDP), which HTTP/3 also (indirectly) always builds on, for example in HTTPU and Simple Service Discovery Protocol (SSDP).

HTTP resources are identified and located on the network by Uniform Resource Locators (URLs), using the Uniform Resource Identifiers (URI's) schemes http and https. As defined in, URIs are encoded as hyperlinks in HTML documents, so as to form interlinked hypertext documents.

In HTTP/1.0 a separate TCP connection to the same server is made for every resource request.

In HTTP/1.1 instead a TCP connection can be reused to make multiple resource requests (i.e. of HTML pages, frames, images, scripts, stylesheets, etc.).

HTTP/1.1 communications therefore experience less latency as the establishment of TCP connections presents considerable overhead, especially under high traffic conditions.

HTTP/2 is a revision of previous HTTP/1.1 in order to maintain the same client–server model and the same protocol methods but with these differences in order:
 * to use a compressed binary representation of metadata (HTTP headers) instead of a textual one, so that headers require much less space;
 * to use a single TCP/IP (usually encrypted) connection per accessed server domain instead of 2 to 8 TCP/IP connections;
 * to use one or more bidirectional streams per TCP/IP connection in which HTTP requests and responses are broken down and transmitted in small packets to almost solve the problem of the HOLB (head-of-line blocking).
 * to add a push capability to allow server application to send data to clients whenever new data is available (without forcing clients to request periodically new data to server by using polling methods).

HTTP/2 communications therefore experience much less latency and, in most cases, even higher speeds than HTTP/1.1 communications.

HTTP/3 is a revision of previous HTTP/2 in order to use QUIC + UDP transport protocols instead of TCP. Before that version, TCP/IP connections were used; but now, only the IP layer is used (which UDP, like TCP, builds on). This slightly improves the average speed of communications and to avoid the occasional (very rare) problem of TCP connection congestion that can temporarily block or slow down the data flow of all its streams (another form of "head of line blocking").

History

The term hypertext was coined by Ted Nelson in 1965 in the Xanadu Project, which was in turn inspired by Vannevar Bush's 1930s vision of the microfilm-based information retrieval and management "memex" system described in his 1945 essay "As We May Think". Tim Berners-Lee and his team at CERN are credited with inventing the original HTTP, along with HTML and the associated technology for a web server and a client user interface called web browser. Berners-Lee designed HTTP in order to help with the adoption of his other idea: the "WorldWideWeb" project, which was first proposed in 1989, now known as the World Wide Web.

The first web server went live in 1990. The protocol used had only one method, namely GET, which would request a page from a server. The response from the server was always an HTML page.

Summary of HTTP milestone versions

 * HTTP/0.9
 * In 1991, the first documented official version of HTTP was written as a plain document, less than 700 words long, and this version was named HTTP/0.9, which supported only GET method, allowing clients to only retrieve HTML documents from the server, but not supporting any other file formats or information upload.

 * HTTP/1.0-draft
 * Since 1992, a new document was written to specify the evolution of the basic protocol towards its next full version. It supported both the simple request method of the 0.9 version and the full GET request that included the client HTTP version. This was the first of the many unofficial HTTP/1.0 drafts that preceded the final work on HTTP/1.0.

 * W3C HTTP Working Group
 * After having decided that new features of HTTP protocol were required and that they had to be fully documented as official RFCs, in early 1995 the HTTP Working Group (HTTP WG, led by Dave Raggett) was constituted with the aim to standardize and expand the protocol with extended operations, extended negotiation, richer meta-information, tied with a security protocol which became more efficient by adding additional methods and header fields.
 * The HTTP WG planned to revise and publish new versions of the protocol as HTTP/1.0 and HTTP/1.1 within 1995, but, because of the many revisions, that timeline lasted much more than one year.
 * The HTTP WG planned also to specify a far future version of HTTP called HTTP-NG (HTTP Next Generation) that would have solved all remaining problems, of previous versions, related to performances, low latency responses, etc. but this work started only a few years later and it was never completed.

 * HTTP/1.0
 * In May 1996, was published as a final HTTP/1.0 revision of what had been used in previous 4 years as a pre-standard HTTP/1.0-draft which was already used by many web browsers and web servers.
 * In early 1996 developers started to even include unofficial extensions of the HTTP/1.0 protocol (i.e. keep-alive connections, etc.) into their products by using drafts of the upcoming HTTP/1.1 specifications.

 * HTTP/1.1
 * Since early 1996, major web browsers and web server developers also started to implement new features specified by pre-standard HTTP/1.1 drafts specifications. End-user adoption of the new versions of browsers and servers was rapid. In March 1996, one web hosting company reported that over 40% of browsers in use on the Internet used the new HTTP/1.1 header "Host" to enable virtual hosting, and that by June 1996, 65% of all browsers accessing their servers were pre-standard HTTP/1.1 compliant.
 * In January 1997, was officially released as HTTP/1.1 specifications.
 * In June 1999, was released to include all improvements and updates based on previous (obsolete) HTTP/1.1 specifications.

 * W3C HTTP-NG Working Group
 * Resuming the old 1995 plan of previous HTTP Working Group, in 1997 an HTTP-NG Working Group was formed to develop a new HTTP protocol named HTTP-NG (HTTP New Generation). A few proposals / drafts were produced for the new protocol to use multiplexing of HTTP transactions inside a single TCP/IP connection, but in 1999, the group stopped its activity passing the technical problems to IETF.

 * IETF HTTP Working Group restarted
 * In 2007, the IETF HTTP Working Group (HTTP WG bis or HTTPbis) was restarted firstly to revise and clarify previous HTTP/1.1 specifications and secondly to write and refine future HTTP/2 specifications (named httpbis).

 * SPDY : an unofficial HTTP protocol developed by Google
 * In 2009, Google, a private company, announced that it had developed and tested a new HTTP binary protocol named SPDY. The implicit aim was to greatly speed up web traffic (specially between future web browsers and its servers).
 * SPDY was indeed much faster than HTTP/1.1 in many tests and so it was quickly adopted by Chromium and then by other major web browsers.
 * Some of the ideas about multiplexing HTTP streams over a single TCP/IP connection were taken from various sources, including the work of W3C HTTP-NG Working Group.

 * HTTP/2
 * In January–March 2012, HTTP Working Group (HTTPbis) announced the need to start to focus on a new HTTP/2 protocol (while finishing the revision of HTTP/1.1 specifications), maybe taking in consideration ideas and work done for SPDY.
 * After a few months about what to do to develop a new version of HTTP, it was decided to derive it from SPDY.
 * In May 2015, HTTP/2 was published as and quickly adopted by all web browsers already supporting SPDY and more slowly by web servers.

 * 2014 updates to HTTP/1.1
 * In June 2014, the HTTP Working Group released an updated six-part HTTP/1.1 specification obsoleting :
 * , HTTP/1.1: Message Syntax and Routing
 * , HTTP/1.1: Semantics and Content
 * , HTTP/1.1: Conditional Requests
 * , HTTP/1.1: Range Requests
 * , HTTP/1.1: Caching
 * , HTTP/1.1: Authentication

 * HTTP/0.9 Deprecation
 * In Appendix-A, HTTP/0.9 was deprecated for servers supporting HTTP/1.1 version (and higher): "Since HTTP/0.9 did not support header fields in a request, there is no mechanism for it to support name-based virtual hosts (selection of resource by inspection of the Host header field). Any server that implements name-based virtual hosts ought to disable support for HTTP/0.9.  Most requests that appear to be HTTP/0.9 are, in fact, badly constructed HTTP/1.x requests caused by a client failing to properly encode the request-target."
 * Since 2016 many product managers and developers of user agents (browsers, etc.) and web servers have begun planning to gradually deprecate and dismiss support for HTTP/0.9 protocol, mainly for the following reasons:
 * it is so simple that an RFC document was never written (there is only the original document);
 * it has no HTTP headers and lacks many other features that nowadays are required for minimal security reasons;
 * it has not been widespread since 1999..2000 (because of HTTP/1.0 and HTTP/1.1) and is commonly used only by some very old network hardware, i.e. routers, etc.

 * HTTP/3
 * In 2020, the first drafts HTTP/3 were published and major web browsers and web servers started to adopt it.
 * On 6 June 2022, IETF standardized HTTP/3 as.

 * Updates and refactoring in 2022
 * In June 2022, a batch of RFCs was published, deprecating many of the previous documents and introducing a few minor changes and a refactoring of HTTP semantics description into a separate document.
 * , HTTP Semantics
 * , HTTP Caching
 * , HTTP/1.1
 * , HTTP/2
 * , HTTP/3 (see also the section above)
 * , QPACK: Field Compression for HTTP/3
 * , Extensible Prioritization Scheme for HTTP

HTTP data exchange
HTTP is a stateless application-level protocol and it requires a reliable network transport connection to exchange data between client and server. In HTTP implementations, TCP/IP connections are used using well-known ports (typically port 80 if the connection is unencrypted or port 443 if the connection is encrypted, see also List of TCP and UDP port numbers). In HTTP/2, a TCP/IP connection plus multiple protocol channels are used. In HTTP/3, the application transport protocol QUIC over UDP is used.

Request and response messages through connections
Data is exchanged through a sequence of request–response messages which are exchanged by a session layer transport connection. An HTTP client initially tries to connect to a server establishing a connection (real or virtual). An HTTP(S) server listening on that port accepts the connection and then waits for a client's request message. The client sends its HTTP request message. Upon receiving the request the server sends back an HTTP response message, which includes header(s) plus a body if it is required. The body of this response message is typically the requested resource, although an error message or other information may also be returned. At any time (for many reasons) client or server can close the connection. Closing a connection is usually advertised in advance by using one or more HTTP headers in the last request/response message sent to server or client.

Persistent connections
In HTTP/0.9, the TCP/IP connection is always closed after server response has been sent, so it is never persistent.

In HTTP/1.0, as stated in RFC 1945, the TCP/IP connection should always be closed by server after a response has been sent.

In HTTP/1.1 a keep-alive-mechanism was officially introduced so that a connection could be reused for more than one request/response. Such persistent connections reduce request latency perceptibly because the client does not need to re-negotiate the TCP 3-Way-Handshake connection after the first request has been sent. Another positive side effect is that, in general, the connection becomes faster with time due to TCP's slow-start-mechanism.

HTTP/1.1 added also HTTP pipelining in order to further reduce lag time when using persistent connections by allowing clients to send multiple requests before waiting for each response. This optimization was never considered really safe because a few web servers and many proxy servers, specially transparent proxy servers placed in Internet / Intranets between clients and servers, did not handle pipelined requests properly (they served only the first request discarding the others, they closed the connection because they saw more data after the first request or some proxies even returned responses out of order etc.). Because of this, only HEAD and some GET requests (i.e. limited to real file requests and so with URLs without query string used as a command, etc.) could be pipelined in a safe and idempotent mode. After many years of struggling with the problems introduced by enabling pipelining, this feature was first disabled and then removed from most browsers also because of the announced adoption of HTTP/2.

HTTP/2 extended the usage of persistent connections by multiplexing many concurrent requests/responses through a single TCP/IP connection.

HTTP/3 does not use TCP/IP connections but QUIC + UDP (see also: technical overview).

Content retrieval optimizations

 * HTTP/0.9
 * A requested resource was always sent in its entirety.

 * HTTP/1.0
 * HTTP/1.0 added headers to manage resources cached by client in order to allow conditional GET requests; in practice a server has to return the entire content of the requested resource only if its last modified time is not known by client or if it changed since last full response to GET request. One of these headers, "Content-Encoding", was added to specify whether the returned content of a resource was or was not compressed.
 * If the total length of the content of a resource was not known in advance (i.e. because it was dynamically generated, etc.) then the header  was not present in HTTP headers and the client assumed that when server closed the connection, the content had been sent in its entirety.  This mechanism could not distinguish between a resource transfer successfully completed and an interrupted one (because of a server / network error or something else).

 * HTTP/1.1
 * HTTP/1.1 introduced:
 * new headers to better manage the conditional retrieval of cached resources.
 * chunked transfer encoding to allow content to be streamed in chunks in order to reliably send it even when the server does not know its length in advance (i.e. because it is dynamically generated, etc.).
 * byte range serving, where a client can request only one or more portions (ranges of bytes) of a resource (i.e. the first part, a part in the middle or in the end of the entire content, etc.) and the server usually sends only the requested part(s). This is useful to resume an interrupted download (when a file is very large), when only a part of a content has to be shown or dynamically added to the already visible part by a browser (i.e. only the first or the following n comments of a web page) in order to spare time, bandwidth and system resources, etc.

 * HTTP/2, HTTP/3
 * Both HTTP/2 and HTTP/3 have kept the above mentioned features of HTTP/1.1.

HTTP authentication
HTTP provides multiple authentication schemes such as basic access authentication and digest access authentication which operate via a challenge–response mechanism whereby the server identifies and issues a challenge before serving the requested content.

HTTP provides a general framework for access control and authentication, via an extensible set of challenge–response authentication schemes, which can be used by a server to challenge a client request and by a client to provide authentication information.

The authentication mechanisms described above belong to the HTTP protocol and are managed by client and server HTTP software (if configured to require authentication before allowing client access to one or more web resources), and not by the web applications using a web application session.

Authentication realms
The HTTP Authentication specification also provides an arbitrary, implementation-specific construct for further dividing resources common to a given root URI. The realm value string, if present, is combined with the canonical root URI to form the protection space component of the challenge. This in effect allows the server to define separate authentication scopes under one root URI.

HTTP application session
HTTP is a stateless protocol. A stateless protocol does not require the web server to retain information or status about each user for the duration of multiple requests.

Some web applications need to manage user sessions, so they implement states, or server side sessions, using for instance HTTP cookies or hidden variables within web forms.

To start an application user session, an interactive authentication via web application login must be performed. To stop a user session a logout operation must be requested by user. These kind of operations do not use HTTP authentication but a custom managed web application authentication.

HTTP/1.1 request messages
Request messages are sent by a client to a target server.

Request syntax
A client sends request messages to the server, which consist of:

 * a request line, consisting of the case-sensitive request method, a space, the requested URL, another space, the protocol version, a carriage return, and a line feed, e.g.:

Host: www.example.com Accept-Language: en
 * zero or more request header fields (at least 1 or more headers in case of HTTP/1.1), each consisting of the case-insensitive field name, a colon, optional leading whitespace, the field value, an optional trailing whitespace and ending with a carriage return and a line feed, e.g.:
 * an empty line, consisting of a carriage return and a line feed;
 * an optional message body.

In the HTTP/1.1 protocol, all header fields except  are optional.

A request line containing only the path name is accepted by servers to maintain compatibility with HTTP clients before the HTTP/1.0 specification in.

Request methods
HTTP defines methods (sometimes referred to as verbs, but nowhere in the specification does it mention verb) to indicate the desired action to be performed on the identified resource. What this resource represents, whether pre-existing data or data that is generated dynamically, depends on the implementation of the server. Often, the resource corresponds to a file or the output of an executable residing on the server. The HTTP/1.0 specification defined the GET, HEAD, and POST methods as well as listing the PUT, DELETE, LINK and UNLINK methods under additional methods. However, the HTTP/1.1 specification formally defined and added five new methods: PUT, DELETE, CONNECT, OPTIONS, and TRACE. Any client can use any method and the server can be configured to support any combination of methods. If a method is unknown to an intermediate, it will be treated as an unsafe and non-idempotent method. There is no limit to the number of methods that can be defined, which allows for future methods to be specified without breaking existing infrastructure. For example, WebDAV defined seven new methods and specified the PATCH method.

Method names are case sensitive. This is in contrast to HTTP header field names which are case-insensitive.

 * GET: The GET method requests that the target resource transfer a representation of its state. GET requests should only retrieve data and should have no other effect. (This is also true of some other HTTP methods.) For retrieving resources without making changes, GET is preferred over POST, as they can be addressed through a URL. This enables bookmarking and sharing and makes GET responses eligible for caching, which can save bandwidth. The W3C has published guidance principles on this distinction, saying, "Web application design should be informed by the above principles, but also by the relevant limitations." See safe methods below.

 * HEAD: The HEAD method requests that the target resource transfer a representation of its state, as for a GET request, but without the representation data enclosed in the response body. This is useful for retrieving the representation metadata in the response header, without having to transfer the entire representation. Uses include checking whether a page is available through the status code and quickly finding the size of a file.

 * POST: The POST method requests that the target resource process the representation enclosed in the request according to the semantics of the target resource. For example, it is used for posting a message to an Internet forum, subscribing to a mailing list, or completing an online shopping transaction.

 * PUT: The PUT method requests that the target resource create or update its state with the state defined by the representation enclosed in the request. A distinction from POST is that the client specifies the target location on the server.

 * DELETE: The DELETE method requests that the target resource delete its state.

 * CONNECT: The CONNECT method requests that the intermediary establish a TCP/IP tunnel to the origin server identified by the request target. It is often used to secure connections through one or more HTTP proxies with TLS. See HTTP CONNECT method.

 * OPTIONS: The OPTIONS method requests that the target resource transfer the HTTP methods that it supports. This can be used to check the functionality of a web server by requesting '*' instead of a specific resource.

 * TRACE: The TRACE method requests that the target resource transfer the received request in the response body. That way a client can see what (if any) changes or additions have been made by intermediaries.

 * PATCH: The PATCH method requests that the target resource modify its state according to the partial update defined in the representation enclosed in the request. This can save bandwidth by updating a part of a file or document without having to transfer it entirely.

All general-purpose web servers are required to implement at least the GET and HEAD methods, and all other methods are considered optional by the specification.

Safe methods
A request method is safe if a request with that method has no intended effect on the server. The methods GET, HEAD, OPTIONS, and TRACE are defined as safe. In other words, safe methods are intended to be read-only. They do not exclude side effects though, such as appending request information to a log file or charging an advertising account, since they are not requested by the client, by definition.

In contrast, the methods POST, PUT, DELETE, CONNECT, and PATCH are not safe. They may modify the state of the server or have other effects such as sending an email. Such methods are therefore not usually used by conforming web robots or web crawlers; some that do not conform tend to make requests without regard to context or consequences.

Despite the prescribed safety of GET requests, in practice their handling by the server is not technically limited in any way. Careless or deliberately irregular programming can allow GET requests to cause non-trivial changes on the server. This is discouraged because of the problems which can occur when web caching, search engines, and other automated agents make unintended changes on the server. For example, a website might allow deletion of a resource through a URL such as  https://example.com/article/1234/delete , which, if arbitrarily fetched, even using GET, would simply delete the article. A properly coded website would require a DELETE or POST method for this action, which non-malicious bots would not make.

One example of this occurring in practice was during the short-lived Google Web Accelerator beta, which prefetched arbitrary URLs on the page a user was viewing, causing records to be automatically altered or deleted en masse. The beta was suspended only weeks after its first release, following widespread criticism.

Idempotent methods
A request method is idempotent if multiple identical requests with that method have the same effect as a single such request. The methods PUT and DELETE, and safe methods are defined as idempotent. Safe methods are trivially idempotent, since they are intended to have no effect on the server whatsoever; the PUT and DELETE methods, meanwhile, are idempotent since successive identical requests will be ignored. A website might, for instance, set up a PUT endpoint to modify a user's recorded email address. If this endpoint is configured correctly, any requests which ask to change a user's email address to the same email address which is already recorded—e.g. duplicate requests following a successful request—will have no effect. Similarly, a request to DELETE a certain user will have no effect if that user has already been deleted.

In contrast, the methods POST, CONNECT, and PATCH are not necessarily idempotent, and therefore sending an identical POST request multiple times may further modify the state of the server or have further effects, such as sending multiple emails. In some cases this is the desired effect, but in other cases it may occur accidentally. A user might, for example, inadvertently send multiple POST requests by clicking a button again if they were not given clear feedback that the first click was being processed. While web browsers may show alert dialog boxes to warn users in some cases where reloading a page may re-submit a POST request, it is generally up to the web application to handle cases where a POST request should not be submitted more than once.

Note that whether or not a method is idempotent is not enforced by the protocol or web server. It is perfectly possible to write a web application in which (for example) a database insert or other non-idempotent action is triggered by a GET or other request. To do so against recommendations, however, may result in undesirable consequences, if a user agent assumes that repeating the same request is safe when it is not.

Cacheable methods
A request method is cacheable if responses to requests with that method may be stored for future reuse. The methods GET, HEAD, and POST are defined as cacheable.

In contrast, the methods PUT, DELETE, CONNECT, OPTIONS, TRACE, and PATCH are not cacheable.

Request header fields
Request header fields allow the client to pass additional information beyond the request line, acting as request modifiers (similarly to the parameters of a procedure). They give information about the client, about the target resource, or about the expected handling of the request.

HTTP/1.1 response messages
A response message is sent by a server to a client as a reply to its former request message.

Response syntax
A server sends response messages to the client, which consist of:
 * a status line, consisting of the protocol version, a space, the response status code, another space, a possibly empty reason phrase, a carriage return and a line feed, e.g.:
 * zero or more response header fields, each consisting of the case-insensitive field name, a colon, optional leading whitespace, the field value, an optional trailing whitespace and ending with a carriage return and a line feed, e.g.:
 * an empty line, consisting of a carriage return and a line feed;
 * an optional message body.
 * an empty line, consisting of a carriage return and a line feed;
 * an optional message body.

Response status codes
In HTTP/1.0 and since, the first line of the HTTP response is called the status line and includes a numeric status code (such as "404") and a textual reason phrase (such as "Not Found"). The response status code is a three-digit integer code representing the result of the server's attempt to understand and satisfy the client's corresponding request. The way the client handles the response depends primarily on the status code, and secondarily on the other response header fields. Clients may not understand all registered status codes but they must understand their class (given by the first digit of the status code) and treat an unrecognized status code as being equivalent to the x00 status code of that class.

The standard reason phrases are only recommendations, and can be replaced with "local equivalents" at the web developer's discretion. If the status code indicated a problem, the user agent might display the reason phrase to the user to provide further information about the nature of the problem. The standard also allows the user agent to attempt to interpret the reason phrase, though this might be unwise since the standard explicitly specifies that status codes are machine-readable and reason phrases are human-readable.

The first digit of the status code defines its class:
 * (informational): The request was received, continuing process.
 * (successful): The request was successfully received, understood, and accepted.
 * (redirection): Further action needs to be taken in order to complete the request.
 * (client error): The request contains bad syntax or cannot be fulfilled.
 * (server error): The server failed to fulfill an apparently valid request.

Response header fields
The response header fields allow the server to pass additional information beyond the status line, acting as response modifiers. They give information about the server or about further access to the target resource or related resources.

Each response header field has a defined meaning which can be further refined by the semantics of the request method or response status code.

HTTP/1.1 example of request / response transaction
Below is a sample HTTP transaction between an HTTP/1.1 client and an HTTP/1.1 server running on www.example.com, port 80.

Client request
A client request (consisting in this case of the request line and a few headers that can be reduced to only the  header) is followed by a blank line, so that the request ends with a double end of line, each in the form of a carriage return followed by a line feed. The  header value distinguishes between various DNS names sharing a single IP address, allowing name-based virtual hosting. While optional in HTTP/1.0, it is mandatory in HTTP/1.1. (A "/" (slash) will usually fetch a /index.html file if there is one.)

Server response
The ETag (entity tag) header field is used to determine if a cached version of the requested resource is identical to the current version of the resource on the server. specifies the Internet media type of the data conveyed by the HTTP message, while  indicates its length in bytes. The HTTP/1.1 webserver publishes its ability to respond to requests for certain byte ranges of the document by setting the field. This is useful, if the client needs to have only certain portions of a resource sent by the server, which is called byte serving. When  is sent, it means that the web server will close the TCP connection immediately after the end of the transfer of this response.

Most of the header lines are optional but some are mandatory. When header  is missing in a response with an entity body then this should be considered an error in HTTP/1.0 but it may not be an error in HTTP/1.1 if header   is present. Chunked transfer encoding uses a chunk size of 0 to mark the end of the content. Some old implementations of HTTP/1.0 omitted the header  when the length of the body entity was not known at the beginning of the response and so the transfer of data to client continued until server closed the socket.

A  can be used to inform the client that the body entity part of the transmitted data is compressed by gzip algorithm.

Encrypted connections
The most popular way of establishing an encrypted HTTP connection is HTTPS. Two other methods for establishing an encrypted HTTP connection also exist: Secure Hypertext Transfer Protocol, and using the HTTP/1.1 Upgrade header to specify an upgrade to TLS. Browser support for these two is, however, nearly non-existent.

Similar protocols

 * The Gopher protocol is a content delivery protocol that was displaced by HTTP in the early 1990s.
 * The SPDY protocol is an alternative to HTTP developed at Google, superseded by HTTP/2.
 * The Gemini protocol is a Gopher-inspired protocol which mandates privacy-related features.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: HTTP