text:
Battle of Tewkesbury

The Battle of Tewkesbury, which took place on 4 May 1471, was one of the most decisive battles of the Wars of the Roses in England.

King Edward IV and his forces loyal to the House of York completely defeated those of the rival House of Lancaster. The Lancastrian heir to the throne, Edward of Westminster, Prince of Wales, and many prominent Lancastrian nobles were killed during the battle or executed. The Lancastrian king, Henry VI, who was a prisoner in the Tower of London, died shortly after the battle, perhaps murdered. Tewkesbury restored political stability to England until the death of Edward IV in 1483.

Background
The term Wars of the Roses refers to the informal heraldic badges of the two rival houses of Lancaster and York, which had been contending for the English throne since the late 1450s. In 1461 the Yorkist claimant, Edward, Earl of March, was proclaimed King Edward IV and defeated the supporters of the weak, intermittently insane Lancastrian King Henry VI at the Battle of Towton. Lancastrian revolts in the far north of England were defeated in 1464, and the fugitive King Henry was captured and imprisoned the next year. His wife, Margaret of Anjou, and their 13-year-old son Edward of Westminster were exiled and impoverished in France. Edward IV's hold on the throne appeared to be secure, at least temporarily.

Edward owed his victory in large measure to the support of his cousin, the powerful 16th Earl of Warwick. They became estranged when Edward spurned the French diplomatic marriage that Warwick was seeking for him and instead married Elizabeth Woodville, widow of an obscure Lancastrian gentleman, in secret in 1464.

When the marriage became public knowledge, Edward placed many of his new queen's family in powerful positions that Warwick had hoped to control. Edward, meanwhile, reversed Warwick's policy of friendship with France by marrying his sister Margaret to Charles the Bold, the Duke of Burgundy. The embittered Warwick secured the support of Edward IV's brother George Plantagenet, 1st Duke of Clarence, for a coup in exchange for Warwick's promise to crown Clarence king. Although Edward was imprisoned briefly, Clarence was unacceptable as monarch to most of the country. Edward was allowed to resume his rule, outwardly reconciled with Warwick and Clarence. Within a year, though, he accused them of fresh treachery and forced them to flee to France.

Readeption of Henry VI
With no hope of a reconciliation with King Edward, Warwick's best hope of regaining power in England lay in restoring Henry VI to the throne. Louis XI of France feared a hostile alliance of Burgundy under Charles the Bold and England under Edward. He was prepared to support Warwick with men and money, but to give legitimacy to any uprising by Warwick, the acquiescence of Margaret of Anjou was required. Warwick and Margaret were previously sworn enemies, but her attendants (in particular Sir John Fortescue, formerly Chief Justice during Henry VI's reign) and Louis eventually persuaded her to ally the House of Lancaster with Warwick.

At Angers Warwick begged her pardon on his knees for all past wrongs done to her, and was forgiven. Prince Edward was betrothed to Warwick's younger daughter Anne (the marriage was eventually solemnised at Amboise on 13 December 1470 but may not have been consummated, as Margaret was seeking a better match for Edward once he was king). Finally they swore loyalty to Henry VI on a fragment of the True Cross in Angers Cathedral. However, Margaret declined to let Prince Edward land in England or to land there herself until Warwick had established a firm government and made the country safe for them.

Warwick landed in the West Country on 13 September 1470, accompanied by Clarence and some unswerving Lancastrian nobles, including the Earl of Oxford and Jasper Tudor, the Earl of Pembroke. As King Edward made his way south to face Warwick, he realised that Warwick's brother John, Marquess of Montagu, who had up until then remained loyal to Edward, had defected at the head of a large army in the north of England. Edward fled to King's Lynn, where he took ship for Flanders, part of Burgundy, accompanied only by his youngest brother Richard of Gloucester and a few faithful adherents.

In London Warwick released King Henry, led him in procession to Saint Paul's cathedral, and installed him in Westminster palace. Warwick's position nevertheless remained precarious. His alliance with Louis of France and his intention to declare war on Burgundy was contrary to the interests of the merchants, as it threatened English trade with Flanders and the Netherlands. Clarence had long been excluded from Warwick's calculations. In November 1470 Parliament declared that Prince Edward and his (putative) descendants were Henry's heirs to the throne; Clarence would become king only if the Lancastrian line of succession failed. Unknown to Warwick, Clarence secretly became reconciled with his brother, King Edward.

Edward's landing and the death of Warwick
With Warwick in power in England, it was Charles of Burgundy's turn to fear a hostile alliance of England and France. As an obvious counter to Warwick, he supplied King Edward with money (50,000 florins), ships, and several hundred men (including handgunners). Edward set sail from Flushing on 11 March 1471 with 36 ships and 1,200 men. He touched briefly on the English coast at Cromer but found that the Duke of Norfolk, who might have supported him, was away from the area and that Warwick controlled that part of the country. Instead, his ships made for Ravenspurn, near the mouth of the River Humber, where Henry Bolingbroke had landed in 1399 on his way to reclaim the Duchy of Lancaster and ultimately depose Richard II.

Edward's landing was inauspicious at first; the ships were scattered by bad weather and his men landed in small detachments over a wide area on 14 March. The port of Kingston-upon-Hull refused to allow Edward to enter, so he made for York, claiming rather like Bolingbroke that he was seeking only the restoration of the Duchy of York. He then began to march south. Near Pontefract Castle he evaded the troops of Warwick's brother Montagu. By the time Edward reached the town of Warwick he had gathered enough supporters to proclaim himself king again. The Earl of Warwick sent urgent requests for Queen Margaret, who was gathering fresh forces in France, to join him in England. He himself was at Coventry, preparing to bar Edward's way to London, while Montagu hastened up behind the king's army.

Edward, however, knew that Clarence was ready to turn his coat once again and betray Warwick, his father-in-law. He marched rapidly west and joined with Clarence's men, who were approaching from Gloucestershire. Clarence appealed to Warwick to surrender, but Warwick refused to even speak to him. Edward's army made rapidly for London, pursued by Warwick and Montagu. London was supposedly defended by the 4th Duke of Somerset, but he was absent and the city readily admitted Edward. The unfortunate and by now feeble Henry VI was sent back to the Tower of London. Edward then turned about to face Warwick's approaching army. On 14 April, they met at the Battle of Barnet. In a confused fight in thick fog, some of Warwick's army attacked each other by mistake, and at the cries of "Treachery!" his army disintegrated and was routed. Montagu died in the battle and Warwick was cut down trying to reach his horse to escape.

The Tewkesbury campaign
Urged on by Louis XI, Margaret finally sailed on 24 March. Storms forced her ships back to France several times, and she and Prince Edward finally landed at Weymouth in Dorsetshire on the same day the Battle of Barnet was fought. While Margaret sheltered at nearby Cerne Abbey, the Duke of Somerset brought news of the disaster at Barnet to her. She briefly wished to return to France, but Prince Edward persuaded her to gamble for victory. Somerset and the Earl of Devon had already raised an army for Lancaster in the West Country. Their best hope was to march northward and join forces with the Lancastrians in Wales, led by Jasper Tudor. Other Lancastrian forces could be relied upon to distract King Edward; in particular, a fleet under Warwick's relation, the Bastard of Fauconberg, was preparing to descend on Kent, where the Nevilles and Warwick, in particular, had always been popular.

In London King Edward had learned of Margaret's landing only two days after she arrived. Although he had given many of his supporters and troops leave after the victory at Barnet, he was nonetheless able to rapidly muster a substantial force at Windsor, just west of London. It was difficult at first to determine Margaret's intentions, as the Lancastrians had sent out several feints that suggested they might be making directly for London, but Edward's army set out for the West Country within a few days.

On 30 April Margaret's army had reached Bath, on its way towards Wales. She turned aside briefly to secure guns, reinforcements, and money from the city of Bristol. On the same day King Edward reached Cirencester. On hearing that Margaret was at Bristol, he turned south to meet her army. However, the Lancastrians made a feint towards Little Sodbury, about 12 mi north-east of Bristol. Nearby was Sodbury Hill, an Iron Age hill fort that was an obvious strategic point for the Lancastrians to seize. When Yorkist scouts reached the hill there was a sharp fight in which they suffered heavy casualties. Believing that the Lancastrians were about to offer battle, Edward temporarily halted his army while the stragglers caught up and the remainder could rest after their rapid march from Windsor. However, the Lancastrians instead made a swift move north by night, passing within 3 mi of Edward's army. By the morning of 2 May, they had gained the safety of Berkeley Castle and had a head start of 15 mi over Edward.

King Edward realized that the Lancastrians were seeking to cross the River Severn into Wales. The nearest crossing point they could use was at the city of Gloucester. He sent urgent messages to the governor, Sir Richard Beauchamp, ordering him to bar the gates to Margaret and man the city's defences. When Margaret arrived on the morning of 3 May, Beauchamp refused her summons to let her army pass, and she realized that there was insufficient time to storm the city before Edward's army arrived. Instead, her army made another forced march of 10 mi to Tewkesbury, attempting to reach the next bridge at Upton-upon-Severn, 7 mi further on. Edward meanwhile had marched no less than 31 mi, passing through Cheltenham (then little more than a village) in the late afternoon. The day was very hot, and both the Lancastrians and Edward's pursuing army were exhausted. The Lancastrians were forced to abandon some of their artillery, which was captured by Yorkist reinforcements following from Gloucester.

At Tewkesbury, the tired Lancastrians halted for the night. Most of their army were footmen and unable to continue further without rest, and even the mounted troops were weary. By contrast, King Edward's army was composed mainly of mounted men, who nevertheless dismounted to fight on foot as most English armies did during this period. Hearing from his "prickers" or mounted scouts of Margaret's position, Edward drove his army to make another march of 6 mi from Cheltenham, finally halting 3 mi from the Lancastrians. The Lancastrians knew they could retreat no further before Edward attacked their rear, and that they would be forced to give battle.

Lancastrian positions
As day broke on 4 May, the Lancastrians took up a defensive position a mile south of the town of Tewkesbury. To their rear were the River Avon and the Severn. Tewkesbury Abbey was just behind the Lancastrian centre. A farmhouse then known as Gobes Hall marked the centre of the Lancastrian position; nearby was "Margaret's camp", earthworks of uncertain age. Queen Margaret is said to have spent the night at Gobes Hall, before hastily taking refuge on the day of battle in a religious house some distance from the battlefield. The main strength of the Lancastrians' position was provided by the ground in front, which was broken up by hedges, woods, embankments, and "evil lanes". This was especially true on their right.

The Lancastrian army numbered approximately 6,000, likely outnumbering the Yorkists by only a few hundred. As was customary at the time, it was organised into three "battles". The right battle was commanded by the Duke of Somerset. A stream, the Colnbrook, flowed through his position, making some of the ground difficult to traverse. The Lancastrian centre was commanded by Lord Wenlock. Unlike the other principal Lancastrian commanders, Wenlock had deserted the Lancastrian cause after the First Battle of Saint Albans, only to revert to the Lancastrians when he was deprived of the Lieutenancy of Calais. Prince Edward was present with the centre. At 17 Prince Edward was no stranger to battlefields, having been given by his mother the task of condemning to death Yorkist prisoners taken at the Second Battle of St Albans, but he lacked experience of actual command. The left battle was commanded by the Earl of Devon, another devoted Lancastrian. His battle, and part of the centre, occupied a low ridge known locally as the "Gastons". A small river, the Swilgate, protected Devon's left flank, before curving behind the Lancastrian position to join the Avon.

Edward's moves
The Yorkists numbered around 5,000–6,000 men. Like the Lancastrians, King Edward organised his army into three battles.

Edward's vanguard was commanded by his youngest brother, Richard, Duke of Gloucester. Although he was only 18 years old, Richard was already an experienced commander and had led a division at the Battle of Barnet. Edward himself commanded the main battle, in which Clarence was also stationed. Edward was 29 years old and at the height of his prowess as a soldier. His lifelong friend and supporter Lord Hastings commanded the rear. He also was an experienced commander and, like Richard, had accompanied Edward into exile in the Low Countries and had led a battle at Barnet.

Although by tradition the vanguard occupied the right of the line of battle, several authors have conjectured from descriptions in near-contemporary accounts (such as the Historie of the arrivall of Edward IV) that Richard of Gloucester's division actually took position to the left of Edward's battle or that the divisions of Edward's army advanced in line ahead, with Edward's division leading.

Edward made one other important tactical disposition. To the left of his army was a thickly wooded park. Concerned that hidden Lancastrians might attack from this quarter, he ordered 200 mounted spearmen to occupy part of the woods and prevent the Lancastrians making use of them, or act on their own initiative if they were not themselves attacked. He then "displayed his bannars: dyd blowe up the trompets: commytted his caws and qwarell to Almyghty God, to owr most blessyd lady his mother: Vyrgyn Mary, the glorious Seint George, and all the saynts: and advaunced, directly upon his enemyes."

Action
As they moved towards the Lancastrian position, King Edward's army found that the ground was so broken up by woods, ditches, and embankments that it was difficult to attack in any sort of order. However, the Yorkist archers and artillery showered the Lancastrians with arrows and shot. The Yorkists certainly had more guns than their enemies, and they were apparently better served.

Either to escape the cannonade and volleys of archery or because he saw an opportunity to outflank King Edward's isolated battle, the Duke of Somerset led at least part of his men via some of the "evil lanes" to attack Edward's left flank. Although taken by surprise, Edward's men resisted stoutly, beating back Somerset's attack among the hedges and banks. At the vital moment, the 200 spearmen Edward had earlier posted in the woods far out on the left attacked Somerset from his own right flank and rear, as Gloucester's battle also joined in the fighting.

Somerset's battle was routed, and his surviving troops tried to escape across the Severn. Most were cut down as they fled. The long meadow astride the Colnbrook leading down to the river is known to this day as "Bloody Meadow". Somerset galloped up to Wenlock, commanding the centre, and demanded to know why Wenlock had failed to support him. According to legend (recounted in Edward Hall's chronicle, written several years afterwards though from first-hand accounts), he did not wait for an answer but dashed out Wenlock's brains with a battleaxe before seeking sanctuary in the Abbey.

As its morale collapsed, the rest of the Lancastrian army tried to flee, but the Swilgate became a deadly barrier. Many who succeeded in crossing it converged on a mill south of the town of Tewkesbury and a weir in the town itself, where there were crossings over the Avon. Here, too, many drowned or were killed by their pursuers.

Aftermath of the battle
Among the leading Lancastrians who died on the field were Somerset's younger brother John Beaufort, Marquess of Dorset, and the Earl of Devon. The Prince of Wales was slain on the field during the retreat by some of Clarence's men, despite pleading for help to Clarence, who had sworn allegiance to him in France barely a year before.

Many of the other Lancastrian nobles and knights sought sanctuary in Tewkesbury Abbey. King Edward attended prayers in the Abbey shortly after the battle. He granted permission for the Prince of Wales and others slain in the battle to be buried within the Abbey or elsewhere in the town without being quartered as traitors as was customary. However, two days after the battle, Somerset and other leaders were dragged out of the Abbey and ordered by Gloucester and the Duke of Norfolk to be put to death after perfunctory trials. Among them were Hugh Courtenay, cousin of the Earls of Devon, and Sir John Langstrother, the prior of the military order of St. John. The Abbey was not officially a sanctuary. It had to be reconsecrated a month after the battle, following the violence done within its precincts.

A few days later Queen Margaret sent word to Edward from her refuge that she was "at his commandment".

Fauconberg's repulse
Edward was unable to rest after the battle. Lancastrians under Jasper Tudor were still active in Wales, and there was an ineffective rising in the North. Edward went to Coventry in the Midlands to make dispositions against the northern and Welsh Lancastrians, and give his army three days' rest. The most dangerous Lancastrian force, however, was that commanded by the Bastard of Fauconberg. As anticipated, he had landed at Sandwich and rapidly recruited a force from among the pro-Neville Kentishmen. Together with exiled Lancastrians and freebooters from several countries, his army may have numbered 16,000 or even 17,000 in total.

On 14 May, he attacked London from the south. His men burned part of the suburb of Southwark, but were beaten back at London Bridge. The next day, they attacked Aldgate and Bishopsgate from the east. The garrison of the Tower of London, led by Earl Rivers, Queen Elizabeth's brother, who had been injured at Barnet, repulsed them. Citizens defending their property undoubtedly played a major role.

Had Fauconberg succeeded in capturing the city, he might also have captured Edward's wife and their children and released King Henry from the Tower. However, on hearing that Edward's army was approaching, he retreated to Sandwich. Like Margaret, he appeared to be dispirited by the news of Tewkesbury and the Prince's death, and later rather tamely surrendered himself and his ships. He was executed five months later after attempting to escape from custody.

End of the Lancastrian royal family
On his way to suppress Fauconberg and the Kentish rebels, Edward passed through London in triumph on 21 May, with the captive Queen Margaret beside him in a chariot. King Henry VI died in the Tower of London that night, at the hands of or by the order of Richard of Gloucester according to several near contemporary accounts. However, the most contemporary account only states that Gloucester was there 'along with many others' and the murder was almost certainly on the orders of the new king, Edward IV. The deposed king's death was announced in public that he had died "of pure displeasure and melancholy", but few believed this.

Gloucester later married Anne Neville, the younger daughter of Warwick and the widow of Henry and Margaret's son Edward.

With the deaths of Somerset and his younger brother, the House of Beaufort, who were distant cousins of Henry VI and had a remote claim to succeed him, had been almost exterminated. Only the female line of Somerset's uncle, the 1st Duke of Somerset, remained, represented by Lady Margaret Beaufort and her son Henry Tudor (later King Henry VII). Henry escaped from Wales with Jasper Tudor, his paternal uncle, and remained in exile in Brittany for the remainder of Edward's reign. The year after the Battle of Tewkesbury, however, Lady Margaret married Lord Stanley, one of King Edward's supporters, who later turned against Edward's brother Richard of Gloucester when he became king as Richard III and was instrumental in putting Henry Tudor on the throne.

Re-enactment
Every year the battle is re-enacted on the second weekend in July at the Tewkesbury Medieval Festival. The event (founded in 1984) is one of the largest events of its kind in Europe, attracting enthusiasts from all over the world.

Monument
The Tewkesbury Battlefield Society erected a monument to the battle in the form of two sculptures 5 m high, of a victorious mounted knight and a defeated horse. Titled Arrivall after the contemporary account of the battle, the work was created by Phil Bews out of green oak wood felled in Gloucestershire, and was dedicated on the anniversary of the battle in 2014.

title: Battle of Tewkesbury


text:
Battle of Barnet

The Battle of Barnet was a decisive engagement in the Wars of the Roses, a dynastic conflict of 15th-century England. The military action, along with the subsequent Battle of Tewkesbury, secured the throne for Edward IV.

On Sunday 14 April 1471, Easter Day, near Barnet, then a small Hertfordshire town north of London, Edward led the House of York in a fight against the House of Lancaster, which backed Henry VI for the throne. Leading the Lancastrian army was Richard Neville, Earl of Warwick, who played a crucial role in the fate of each king. Historians regard the battle as one of the most important clashes in the Wars of the Roses, since it brought about a decisive turn in the fortunes of the two houses. Edward's victory was followed by 14 years of Yorkist rule over England.

Formerly a key figure in the Yorkist cause, Warwick defected to the Lancastrians over disagreements about Edward's nepotism, secret marriage, and foreign policy. Leading a Lancastrian army, the earl defeated his former allies, forcing Edward to flee to Burgundy in October 1470. The Yorkist king persuaded his host, Charles the Bold, the Duke of Burgundy, to help him regain the English throne. Leading an army raised with Burgundian money, Edward launched his invasion of England, which culminated at the fields north of Barnet. Under cover of darkness, the Yorkists moved close to the Lancastrians and clashed in a thick fog at dawn. As both armies fought, the Earl of Oxford on the Lancastrian right routed the Yorkists opposite under Lord Hastings, chasing them back to Barnet. On their return to the battlefield, Oxford's men were erroneously shot at by the Lancastrian centre commanded by Lord Montagu. As cries of treason (always a possibility in that chaotic period) spread through their line, Lancastrian morale was disrupted and many abandoned the fight. While retreating, Warwick was killed by Yorkist soldiers.

Warwick had been such an influential figure in 15th-century English politics that, on his death, no one matched him in terms of power and popularity. Deprived of Warwick's support, the Lancastrians suffered their final defeat at the Battle of Tewkesbury on 4 May, which marked the end of the reign of Henry VI and the restoration of the House of York. Three centuries after the Battle of Barnet, a stone obelisk was raised on the spot where Warwick purportedly died.

Background
The Wars of the Roses were a series of conflicts between various English lords and nobles in support of two different royal families descended from Edward III. In 1461 the conflict reached a milestone when the House of York supplanted its rival, the House of Lancaster, as the ruling royal house in England. Edward IV, leader of the Yorkists, seized the throne from the Lancastrian king, Henry VI, who was captured in 1465 and imprisoned in the Tower of London. His wife, Margaret of Anjou, and their son, Edward of Westminster, fled to Scotland and organised resistance. Edward IV crushed the uprisings and pressured the Scottish government to force Margaret out; the House of Lancaster went into exile in France. As the Yorkists tightened their hold over England, Edward rewarded his supporters, including his chief adviser, Richard Neville, 16th Earl of Warwick, elevating them to higher titles and awarding them land confiscated from their defeated foes. The Earl grew to disapprove of the King's rule, however, and their relationship later became strained.

Warwick had planned for Edward to marry a French princess—Bona of Savoy, sister-in-law to Louis XI of France—to create an alliance between the two countries. The young king, however, favoured ties with Burgundy and, in 1464, further angered the Earl by secretly marrying Elizabeth Woodville; as an impoverished Lancastrian widow, she was regarded by the Yorkists as an unsuitable queen. Edward bestowed gifts of land and titles on her relations and arranged their marriages to rich and powerful families. Eligible bachelors were paired with the Woodville females, narrowing the marriage prospects for Warwick's daughters. Furthermore, the Earl was offended by two matches involving his kin. The first was the marriage of his aunt, Lady Katherine Neville, over 60 years old, to Elizabeth's 20-year-old brother, John Woodville, a pairing considered outside of normal wedlock by many people. The other was his nephew's fiancée, the daughter of Henry Holland, 3rd Duke of Exeter, who was taken as a bride by the Queen's son, Thomas Grey, with Edward's approval. Exasperated by these acts, Warwick decided the Woodvilles were a malignant influence on his liege. He felt marginalized: his influence over the young king was failing, and he decided to take drastic action to force Edward's compliance. Warwick's alternative plan was to replace the King with his fellow conspirator, the Duke of Clarence, Edward's younger brother.

Instigating several rebellions in the north, Warwick lured the King away from his main bastion of support in the south. Edward found himself outnumbered; while retreating, he learned that Warwick and Clarence had called for open support of the rebellion. After winning the Battle of Edgcote on 26 July 1469, the Earl found the Yorkist king deserted by his followers, and brought him to Warwick Castle for "protection". Lancastrian supporters took advantage of Edward's imprisonment to stage uprisings. Because most Yorkist-aligned warlords refused to rally to Warwick's call, the Earl was pressured to release the King. Back in power, Edward did not openly pursue Warwick's transgressions against him, but the Earl suspected that the King held a grudge. Warwick engineered another rebellion, this time to replace Edward with Clarence. The two conspirators, however, had to flee to France when Edward crushed the uprising—the Battle of Losecoat Field—on 12 March 1470. Through letters in the rebels' possession and confessions from the leaders, the King uncovered the Earl's betrayal. In a deal brokered by the French king, Louis XI, the Earl agreed to serve Margaret and the Lancastrian cause. Warwick invaded England at the head of a Lancastrian army and, in October 1470, forced Edward to seek refuge in Burgundy, then ruled by the King's brother-in-law Charles the Bold. The throne of England was temporarily restored to Henry VI; on 14 March 1471, Edward brought an army back across the English Channel, precipitating the Battle of Barnet a month later.

Yorkist
Edward IV was normally at the forefront of his armies. Standing 6 ft, he was an inspiring figure in combat, attacking foes while wearing a suit of gilded armour. Medieval texts describe the King as handsome, finely muscled and with a broad chest. He was personable and charismatic, easily winning people to his cause. Edward was a capable tactician and leader in battles. He frequently spotted and exploited defensive frailties in enemy lines, often with decisive results. By 1471 the young king was a highly respected field commander. He received some criticism, however; after winning the throne in 1461, he proved indecisive about putting down rebellions. Historian Charles Ross praises Edward's leadership and skill in close combat rather than his strategies and tactics.

With his good looks and capable leadership, Edward was popular among the common people, especially compared to Henry VI. His trade policies, which aimed to expand and protect markets for English commerce, pleased local merchants, who were also won over by the Yorkist king's personality. By 1469 Edward's groundswell of popular support had eroded. The euphoria of a change in government had ebbed and the people blamed Edward for failing to "bring the realm of England in[to] great popularity and rest" and allowing Yorkist nobles to go unpunished for abuses. When Edward invaded England in 1471, not many common people openly celebrated his return.

Edward was joined at Barnet by his brothers, Richard, Duke of Gloucester, and George, Duke of Clarence. Unlike his eldest brother, Gloucester was slender and seemingly delicate. He was 18 years old at the Battle of Barnet, his first major engagement. His military prowess, however, was well respected; many historians judge him a capable warrior and military leader. Clarence was not as well regarded as his brothers, especially in matters of loyalty. When Edward became king, Clarence became his heir; however, Edward's marriage to Elizabeth Woodville threatened to displace the Duke in the line of succession to the throne. Hence, Clarence participated in Warwick's schemes, marrying the Earl's daughter Isabel, believing he could gain his brother's throne. Clarence lost faith in the Earl when Warwick defected to the Lancastrians and married off his other daughter, Anne, to their prince in order to cement his new allegiance. When Edward launched his campaign to retake England, Clarence accepted his brother's offer of pardon and rejoined the Yorkists at Coventry on 2 April 1471. The last of the Yorkist commanders was William, Lord Hastings, a loyal subject since the start of the wars. Hastings had accompanied the young king in exile and supported his return. The courtier was rewarded for his faithfulness, gaining the lieutenancy of Calais in 1471 and becoming Edward's lord chamberlain and primary confidant.

Lancastrian
Warwick had fought for the House of York since the early stages of the Wars of the Roses and alongside his cousin, Edward IV, in many of the battles. His years of loyalty earned him the trust of the Yorkists, and his victories—both political and military—and popularity with the common people made him an important figure. He had powerful influence over the line of succession, earning him the nickname "The Kingmaker". Early historians described him as a military genius, but by the 20th century his tactical acumen was reconsidered; Philip Haigh suspects that the Earl largely owed some of his victories, such as the First Battle of St Albans, to being in the right place at the right time. Christopher Gravett believes the Earl was too defensive and lacked mental flexibility.

John Neville, 1st Marquess of Montagu, was less ambitious than his brother Warwick, but a more capable warrior and tactician. In 1464 he commanded a Yorkist force that turned the tables on a Lancastrian ambush at the Battle of Hedgeley Moor and launched a surprise attack at the Battle of Hexham. These victories capped Neville's extensive service in the north, and Edward rewarded him with the Earldom of Northumberland, which bore substantial income. The gift was particularly gratifying for Neville; his family had experienced a deep feud with the former earls of Northumberland, the Percys, who supported the House of Lancaster. However, in March 1470, Edward, trying to win over the Percys' support, reinstated Henry Percy to the earldom. As recompense, Neville received the grander title of Marquess of Montagu; however, the lands accompanying this rank were much poorer than the estate he had lost. The new marquess saw it as an insult—an insubstantial title that was inadequate recognition for his years of faithful service. Montagu did not immediately join Warwick's rebellion, however; he defected later in the year when his brother invaded England.

Not much is known about the early history of John de Vere, 13th Earl of Oxford, another Lancastrian commander; the chronicles mention little about him until the Battle of Losecoat Field. His father, the previous earl and a loyal Lancastrian, was executed for a failed plot to assassinate Edward IV. The Yorkist king tried to secure the loyalty of Oxford by knighting him and pardoning his transgressions. This tactic failed; Oxford remained true to the Lancastrian crown and participated in Warwick's effort to dethrone Edward. Historians describe the young Oxford as a decent military leader, exemplified by his conduct in the Battle of Barnet.

Although Henry Holland, 3rd Duke of Exeter, was of royal blood, he was commonly viewed as a criminal, prone to violence and stupidity. A proven enemy of the Nevilles, Exeter bore a grudge particularly against Warwick for displacing him from his hereditary role of Lord High Admiral in 1457. Nonetheless, when Warwick joined the Lancastrians, Exeter obeyed Margaret and served under the Earl during the invasion of England. Although he supported the Lancastrian cause, Exeter had family ties to the House of York; he was husband to Anne of York, Edward's sister.

Prelude
On 14 March 1471, Edward's army landed at Ravenspurn. Gathering more men as they went, the Yorkists moved inland towards York. Edward's march was unopposed at the beginning because he was moving through lands that belonged to the Percys, and the Earl of Northumberland was indebted to the Yorkist king for the return of his northern territory. Furthermore, Edward announced that he was returning only to claim his father's title of Duke of York and not to contest the English crown. The ruse was successful: Montagu, who was monitoring Edward's march, could not convince his men to move against the Yorkist king.

Once Edward's force had gathered sufficient strength, he dropped the ruse and headed south towards London. Fighting off Exeter's and Oxford's attacks, he besieged Warwick at Coventry, hoping to engage the earl in battle. Although Warwick's force had more men than Edward's army, the earl refused the challenge. He was waiting for the arrival of Clarence, who wanted to use their combined strength to overwhelm the Yorkists. When he learned of this, Edward sent Gloucester to entreat Clarence to return to the House of York, an offer that Clarence readily accepted. Reconciled, the royal brothers moved towards Coventry, and Clarence urged Warwick's surrender. Infuriated with his son-in-law's treachery, Warwick refused to speak to Clarence. Unable to fight the earl at this time, Edward turned again towards London.

Reinforced by Montagu, Oxford and Exeter a few days later, Warwick followed the Yorkists' trail. He hoped that London, under Somerset's control, would close its gates to Edward, allowing him to catch the Yorkist army in the open. The city, however, welcomed Edward warmly; Somerset had left the city and the London populace preferred the young Yorkist king to Henry VI. The old king greeted his usurper warmly and offered himself into custody, trusting "[his] life to be in no danger in [Edward's] hands." Lancastrian scouts probed Barnet, which lay 19 km north of London, but were beaten off. On 13 April their main army took up positions on a ridge of high ground north of Barnet to prepare for battle the next day. Warwick arrayed his army in a line from east to west, on either side of the Great North Road running through Barnet. Oxford held the right flank and Exeter the left. Montagu commanded the centre, and Warwick readied himself to command from among the reserves. The earl displaced his entire line slightly to the west; a depression at the rear of his left flank could impede Exeter's group if they had to fall back.

Warwick's army heavily outnumbered Edward's, although sources differ on exact numbers. Lancastrian strength ranges from 10,000 to 30,000 men, with 7,000–15,000 on the Yorkist side. Facing this disadvantage, Edward hurried to meet the Lancastrians with a surprise attack. He brought Henry VI along to prevent the Lancastrians from retaking their king. Edward reached Barnet in the evening, and without knowing the precise location of his foes, prepared the battle line. The Yorkist king deployed Hastings on the left and entrusted Gloucester to lead the right flank. Clarence would fight alongside Edward in the centre, although this was not due to faith in his ability—it was easier for the Yorkists to keep an eye on their twice-defected prince there. A contingent of reserves was kept at the rear, ready to deploy at Edward's call. As night fell, Edward put his plan for surprise morning attack in motion. Under a strict order of silence, the Yorkist army crept closer to the Lancastrians. During the night, neither commander spotted the opposing army, an event that proved crucial in the battle the next day.

During the night, Warwick ordered his cannons to continually bombard the estimated position of the Yorkists' encampment. The Yorkists, however, had sneaked in close, and the Lancastrian artillery overshot their enemies. The Yorkist cannon, meanwhile, kept quiet to avoid betraying their location. As the armies settled down to rest, Montagu approached his brother and advised him of the troops' low morale. He suggested that, as the highest-ranking commanders, the brothers should fight on foot throughout the battle instead of riding on horse. The soldiers believed that mounted commanders tended to abandon them when the situation deteriorated. By staying on foot, the Nevilles would show that they were prepared to fight to the death with the men, inspiring the troops to stand and fight harder. Warwick agreed and the horses were tethered to the rear, near Wrotham Wood.

Fighting in the mist

On 14 April 1471, at around 4 o'clock in the morning, both armies woke. Edward had planned for an early attack, however, and quickly roused his men to engage the Lancastrians. Both sides fired their cannon and arrows before laying into each other with polearms. The morning fog was thick and the night movements of the two forces had displaced them laterally with each other. Neither group was facing the other; each was offset slightly to the right. This displacement meant that the right end of either army could outflank the other by wrapping around the opposing left end. The Lancastrians were the first to exploit this advantage; Oxford's group quickly overwhelmed Hastings'. Yorkist soldiers fled towards Barnet, chased by the Lancastrians. Some of Hastings' men even reached London, spreading tales of the fall of York and a Lancastrian victory. Oxford's group disintegrated as they split off to loot the fallen enemies and plunder Barnet. Yelling and chasing after his men, Oxford rallied 800 of them and led them back to the battle.

Due to the fog, visibility was low and the two main forces failed to notice Oxford's victory over Hastings. Accordingly, the collapse of the Yorkist left wing had little (if any) effect on morale of either side. The fighting between Montagu's and Edward's groups was evenly matched and intense. The Lancastrian left wing, however, was suffering treatment similar to that Oxford had inflicted on its counterpart; Gloucester exploited the misaligned forces and beat Exeter back. Progress for Edward's brother was slow because his group was fighting up a slight slope. Nonetheless, the pressure he exerted on the Lancastrian left wing rotated the entire battle line. Warwick, seeing the shift, ordered most of his reserves to help ease the pressure on Exeter, and took the rest into fighting at the centre. Gradually, the battle line settled to an orientation that slanted north-east to south-west.

Oxford retraced his steps through the fog back to the fight. His group arrived, unexpectedly, at Montagu's rear. Obscured by the fog, Oxford's "star with rays" badge was mistaken by Montagu's men for Edward's "sun in splendour". They assumed their allies were Edward's reserves and unleashed a volley of arrows. Oxford and his men immediately cried treachery; as staunch Lancastrians, they were wary of Montagu's recent defection. They struck back and began withdrawing from the battle. Their shouts of treason were taken up and spread quickly throughout the Lancastrian line, breaking it apart as men fled in anger, panic and confusion. As the fog started to dissipate, Edward saw the Lancastrian centre in disarray and sent in his reserves, hastening its collapse. Cries of Exeter's demise from a Yorkist axe resounded across the battlefield from the Lancastrian left, and amidst the confusion, Montagu was struck in his back and killed by either a Yorkist or one of Oxford's men.

Witnessing his brother's death, Warwick knew the battle was lost. He made for the horses in an attempt to retreat. Edward recognised his victory was at hand, and—deciding that Warwick was more valuable alive than dead—sent the order and dispatched his guards to bring back the earl alive. Several chroniclers have suggested that the king thought Warwick would again be a valuable ally if persuaded back to the Yorkist cause. Historian Michael Hicks, in contrast, suggests that Edward wanted to capture the earl for public execution rather than as a gesture of mercy. Regardless of the king's intent, Warwick died in the Lancastrian rout: when fleeing the field he was struck off his horse and killed.

A miniature model reproduction of the Battle of Barnet can be found at the Battle's natural interpretive centre, The Barnet Museum.

Post-battle
The battle lasted from two to three hours, and was over by the time the fog lifted in the early morning. As usual in most battles of the time, the routed army suffered far more casualties; fleeing men were cut down from behind. Contemporary sources give various casualty figures; the "Great Chronicle of London" reports 1,500 dead, whereas "Warkworth's Chronicle" states 4,000. Edward Hall and Raphael Holinshed, both 16th-century chroniclers, say that at least 10,000 men died in the battle. The Yorkists suffered half as many casualties as the Lancastrians. Royle favours the recorded approximate figures of 500 Yorkists and 1,000 Lancastrians dead.

The bodies of the two Neville brothers were brought back to London. They did not suffer the customary fate accorded to traitors—quartering and display at the city gates. Edward exhibited the brothers' naked corpses in St. Paul's Cathedral for three days to quell any rumours that they had survived, before allowing them to be laid to rest in the family vault at Bisham Abbey.

Although he had defeated the Neville brothers, Edward had little time to rest; Margaret landed at Weymouth on the day of the battle. She feigned a march to London while augmenting her army with recruits from Wales and the Welsh Marches. The Lancastrian queen was disheartened by the news of Warwick's demise, but Somerset suggested that they were better off without the earl. Despite the defeat at Barnet, Lancastrians who fled from the battle looked to the queen to restore their house to the throne. Alerted by his spies to the Lancastrians' true route, Edward intercepted and defeated them at the Battle of Tewkesbury on 4 May. Gloucester, Clarence and Hastings again fought to defend the Yorkist crown.

Exeter had been stripped of his armour and left for dead on the battlefield at Barnet, but he was alive—though gravely injured. His followers found him and took him to Westminster Abbey. On his recovery, he was imprisoned in the Tower of London for four years before submitting to Edward's rule. Exeter did not participate in the later battles of the Wars of the Roses. Edward sent him on a Yorkist expedition to France in 1475, and the duke was reported to have fallen overboard and drowned without any witnesses.

After withdrawing from the battle, Oxford fled to France and participated in attacks on English ships, continuing his campaign against Yorkist rule. He was captured in 1473 after seizing St Michael's Mount, an island off the southwest coast of England. Twelve years later Oxford escaped from prison and joined Henry Tudor's fight against the Yorkists, commanding the Lancastrian army at the Battle of Bosworth Field in 1485.

Legacy
The Battle of Barnet was an important engagement in the Wars of the Roses: it brought about the death of a prominent figure and secured the throne for another. Despite its importance to history, contemporary records about the battle are rare. The sole chronicle based on an eyewitness account—The Arrivall of Edward IV—was written by someone within Edward's council, which presents a biased account of the battle. Another first-hand observation was found in the Paston Letters, written by the Lancastrian Sir John Paston. Other records, such as The Warkworth Chronicle, offer only bits and pieces about the battle. Therefore, deficits in historical understanding must be filled through field research and discoveries of mediaeval documents.

Historians theorise that had Warwick's force joined Margaret's before challenging Edward, the combined Lancastrian army would have overwhelmed the Yorkists. Instead, Warwick's defeat gave the Yorkists a victory so decisive that it, along with the Battle of Tewkesbury, secured the English throne for Edward IV. Historian Colin Richmond believes that Edward's return to power was assured at Barnet—Tewkesbury was "merely an epilogue". Without having to contend with Warwick's popularity and political influence, the young Yorkist king could fully exert his will and rule the land unchallenged. Ballads composed during Edward's reign celebrated his victory as sanctioned by God: "Man proposes, oftimes in veyn, But God disposes, the boke telleth pleyn". Barnet was a disaster for the Nevilles; their lands given away and their offices reduced. The family never again reached the prominence in English politics that they had enjoyed before the battle.

Shakespearian dramatisation

The battle is alluded to in William Shakespeare's Henry VI, Part 3 (1595). The end of Act V, scene one depicts the events leading up to the battle; scenes two and three portray the conclusion, in which the characters discuss the combat and the fates of its participants. Shakespeare uses few details reported by contemporary chroniclers and ignores notable incidents, such as the confusion over Oxford's and Edward's badges. His play is based mostly on poetic and dramatic sources. In the play, Montagu is killed while trying to save his brother (Shakespeare's source material included Hall's 1548 The Union of the Two Noble and Illustrate Famelies of Lancastre and Yorke), and Warwick is dragged in by Edward IV and left to speak his dying words to Oxford and Somerset. Warwick's death dominates the scenes, reflecting Hall's vivid portrayal of the earl's passing as a valiant death. Furthermore, whereas several chronicles mention Edward's desire to capture Warwick, Shakespeare has the Yorkist king lustily demand Warwick's skin.

Shakespeare presents the Nevilles as brothers who are willing to die for each other, whereas the three sons of York—Edward, Gloucester, and Clarence—are slowly driven apart by their own goals and ideas. Professor of English John Cox suggests that Shakespeare did not share the impression given in post-battle ballads that Edward's triumph was divinely ordained. He argues that Shakespeare's placement of Clarence's last act of betrayal immediately before the battle suggests that Edward's rule stems from his military aggression, luck, and "policy". Shakespeare also explicitly excludes Edward from action sequences, a departure from Hall's depictions.

Battlefield

English Heritage, a government body in charge of conservation of historic sites, roughly locates the battlefield in an area 800 to 1600 metres (0.5 to 1.0 mile) north of the town of Barnet. Over the centuries, much of the terrain has changed, and records of the town's boundaries and geography are not detailed enough for English Heritage or historians to conclude the exact location of the battle. Geographical features corresponding to contemporary descriptions allow approximations of where the fighting took place.

English Heritage suggests that a 15th-century letter from a Hanseatic merchant, Gerhard von Wessel, helps to identify the battlefield via geological features. It mentions a "broad green" which corresponds to Hadley Green, and the marsh on the right flank of the Yorkist line is likely to be in the valley of the Monken Mead Brook. The letter also mentions St Albans road, which has remained largely the same, winding through the fields. Urbanisation over the 18th and 19th centuries, however, has populated much of the area with buildings. By the 20th century, the suburb of Monken Hadley covered part of the fields where the Battle of Barnet was fought. A hedge in the local golf course, as suggested by Lieutenant-Colonel Alfred H. Burne, is likely the row of shrubs behind which Oxford's men lined up and took cover.

In 1740 Sir Jeremy Sambroke erected an obelisk to commemorate the battle about 200 m south of the junction between the Great North Road and Kitts End Road. It was later moved just north of the junction on the grass between the two roads. Known as Hadley Highstone, it stands 5.5 m tall and marks its location with the inscription: ""Here was fought the Famous Battle Between Edward the 4th and the Earl of Warwick April the 14th ANNO 1471 in which the Earl was Defeated And Slain.""

The battle is referred to in the coat of arms of the London Borough of Barnet which display a red and a silver rose in the top of the shield and two crossed swords in the crest.

Every year, the Barnet Medieval Festival is held at the place where the battle is thought to have occurred. It features a re-enactment of the battle and market stalls.

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

title: Battle of Barnet


text:
Chemical warfare

Chemical warfare (CW) involves using the toxic properties of chemical substances as weapons. This type of warfare is distinct from nuclear warfare, biological warfare and radiological warfare, which together make up CBRN, the military acronym for chemical, biological, radiological, and nuclear (warfare or weapons), all of which are considered "weapons of mass destruction" (WMDs), a term that contrasts with conventional weapons.

The use of chemical weapons in international armed conflicts is prohibited under international humanitarian law by the 1925 Geneva Protocol and the Hague Conventions of 1899 and 1907. The 1993 Chemical Weapons Convention prohibits signatories from acquiring, stockpiling, developing, and using chemical weapons in all circumstances except for very limited purposes (research, medical, pharmaceutical or protective).

Definition
Chemical warfare is different from the use of conventional weapons or nuclear weapons because the destructive effects of chemical weapons are not primarily due to any explosive force. The offensive use of living organisms (such as anthrax) is considered biological warfare rather than chemical warfare; however, the use of nonliving toxic products produced by living organisms (e.g. toxins such as botulinum toxin, ricin, and saxitoxin) is considered chemical warfare under the provisions of the Chemical Weapons Convention (CWC). Under this convention, any toxic chemical, regardless of its origin, is considered a chemical weapon unless it is used for purposes that are not prohibited (an important legal definition known as the General Purpose Criterion).

About 70 different chemicals have been used or were stockpiled as chemical warfare agents during the 20th century. The entire class, known as Lethal Unitary Chemical Agents and Munitions, has been scheduled for elimination by the CWC.

Under the convention, chemicals that are toxic enough to be used as chemical weapons, or that may be used to manufacture such chemicals, are divided into three groups according to their purpose and treatment:
 * Schedule 1 – Have few, if any, legitimate uses. These may only be produced or used for research, medical, pharmaceutical or protective purposes (i.e. testing of chemical weapons sensors and protective clothing). Examples include nerve agents, ricin, lewisite and mustard gas. Any production over 100 g must be reported to the Organisation for the Prohibition of Chemical Weapons (OPCW) and a country can have a stockpile of no more than one tonne of these chemicals.
 * Schedule 2 – Have no large-scale industrial uses, but may have legitimate small-scale uses. Examples include dimethyl methylphosphonate, a precursor to sarin also used as a flame retardant, and thiodiglycol, a precursor chemical used in the manufacture of mustard gas but also widely used as a solvent in inks.
 * Schedule 3 – Have legitimate large-scale industrial uses. Examples include phosgene and chloropicrin. Both have been used as chemical weapons but phosgene is an important precursor in the manufacture of plastics, and chloropicrin is used as a fumigant. The OPCW must be notified of, and may inspect, any plant producing more than 30 tons per year.

Chemical weapons are divided into three categories:
 * Category 1 – based on Schedule 1 substances
 * Category 2 – based on non-Schedule 1 substances
 * Category 3 – devices and equipment designed to use chemical weapons, without the substances themselves

History
Simple chemical weapons were used sporadically throughout antiquity and into the Industrial Age. It was not until the 19th century that the modern conception of chemical warfare emerged, as various scientists and nations proposed the use of asphyxiating or poisonous gasses.

Multiple international treaties were passed banning chemical weapons based upon the alarm of nations and scientists. This however did not prevent the extensive use of chemical weapons in World War I. The development of chlorine gas, among others, was used by both sides to try to break the stalemate of trench warfare. Though largely ineffective over the long run, it decidedly changed the nature of the war. In many cases the gasses used did not kill, but instead horribly maimed, injured, or disfigured casualties. Some 1.3 million gas casualties were recorded, which may have included up to 260,000 civilian casualties.

The interwar years saw the occasional use of chemical weapons, mainly to put down rebellions. In Nazi Germany, much research went into developing new chemical weapons, such as potent nerve agents. However, chemical weapons saw little battlefield use in World War II. Both sides were prepared to use such weapons, but the Allied Powers never did, and the Axis used them only very sparingly. The reason for the lack of use by the Nazis, despite the considerable efforts that had gone into developing new varieties, might have been a lack of technical ability or fears that the Allies would retaliate with their own chemical weapons. Those fears were not unfounded: the Allies made comprehensive plans for defensive and retaliatory use of chemical weapons, and stockpiled large quantities. Japanese forces, as part of the Axis, used them more widely, though only against their Asian enemies, as they also feared that using it on Western powers would result in retaliation. Chemical weapons were frequently used against the Kuomintang and Chinese communist troops, the People's Liberation Army. However, the Nazis did extensively use poison gas against civilians, mostly the genocide of European Jews, in The Holocaust. Vast quantities of Zyklon B gas and carbon monoxide were used in the gas chambers of Nazi extermination camps, resulting in the overwhelming majority of some three million deaths. This remains the deadliest use of poison gas in history. The post-war era has seen limited, though devastating, use of chemical weapons. Some 100,000 Iranian troops were casualties of Iraqi chemical weapons during the Iran–Iraq War. Iraq used mustard gas and nerve agents against its own civilians in the 1988 Halabja chemical attack. The Cuban intervention in Angola saw limited use of organophosphates. Terrorist groups have also used chemical weapons, notably in the Tokyo subway sarin attack and the Matsumoto incident. See also chemical terrorism.

In the 21st century, the Ba'athist regime in Syria has used chemical weapons against civilian populations, resulting in numerous deadly chemical attacks during the Syrian civil war. The Syrian government has used sarin, chlorine, and mustard gas in the Syrian civil war – mostly against civilians.

Russia has used chemical weapons against the Ukrainians during the Ukraine war. This has been done mainly by dropping a grenade with K-51 aerosol CS gas from an unmanned drone.

Technology

Although crude chemical warfare has been employed in many parts of the world for thousands of years, "modern" chemical warfare began during World War I – see Chemical weapons in World War I.

Initially, only well-known commercially available chemicals and their variants were used. These included chlorine and phosgene gas. The methods used to disperse these agents during battle were relatively unrefined and inefficient. Even so, casualties could be heavy, due to the mainly static troop positions which were characteristic features of trench warfare.

Germany, the first side to employ chemical warfare on the battlefield, simply opened canisters of chlorine upwind of the opposing side and let the prevailing winds do the dissemination. Soon after, the French modified artillery munitions to contain phosgene – a much more effective method that became the principal means of delivery.

Since the development of modern chemical warfare in World War I, nations have pursued research and development on chemical weapons that falls into four major categories: new and more deadly agents; more efficient methods of delivering agents to the target (dissemination); more reliable means of defense against chemical weapons; and more sensitive and accurate means of detecting chemical agents.

Chemical warfare agents
The chemical used in warfare is called a chemical warfare agent (CWA). About 70 different chemicals have been used or stockpiled as chemical warfare agents during the 20th and 21st centuries. These agents may be in liquid, gas or solid form. Liquid agents that evaporate quickly are said to be volatile or have a high vapor pressure. Many chemical agents are volatile organic compounds so they can be dispersed over a large region quickly.

The earliest target of chemical warfare agent research was not toxicity, but development of agents that can affect a target through the skin and clothing, rendering protective gas masks useless. In July 1917, the Germans employed sulfur mustard. Mustard agents easily penetrate leather and fabric to inflict painful burns on the skin.

Chemical warfare agents are divided into lethal and incapacitating categories. A substance is classified as incapacitating if less than 1/100 of the lethal dose causes incapacitation, e.g., through nausea or visual problems. The distinction between lethal and incapacitating substances is not fixed, but relies on a statistical average called the.

Persistency
Chemical warfare agents can be classified according to their persistency, a measure of the length of time that a chemical agent remains effective after dissemination. Chemical agents are classified as persistent or nonpersistent.

Agents classified as nonpersistent lose effectiveness after only a few minutes or hours or even only a few seconds. Purely gaseous agents such as chlorine are nonpersistent, as are highly volatile agents such as sarin. Tactically, nonpersistent agents are very useful against targets that are to be taken over and controlled very quickly.

Apart from the agent used, the delivery mode is very important. To achieve a nonpersistent deployment, the agent is dispersed into very small droplets comparable with the mist produced by an aerosol can. In this form not only the gaseous part of the agent (around 50%) but also the fine aerosol can be inhaled or absorbed through pores in the skin.

Modern doctrine requires very high concentrations almost instantly in order to be effective (one breath should contain a lethal dose of the agent). To achieve this, the primary weapons used would be rocket artillery or bombs and large ballistic missiles with cluster warheads. The contamination in the target area is only low or not existent and after four hours sarin or similar agents are not detectable anymore.

By contrast, persistent agents tend to remain in the environment for as long as several weeks, complicating decontamination. Defense against persistent agents requires shielding for extended periods of time. Nonvolatile liquid agents, such as blister agents and the oily VX nerve agent, do not easily evaporate into a gas, and therefore present primarily a contact hazard.

The droplet size used for persistent delivery goes up to 1 mm increasing the falling speed and therefore about 80% of the deployed agent reaches the ground, resulting in heavy contamination. Deployment of persistent agents is intended to constrain enemy operations by denying access to contaminated areas.

Possible targets include enemy flank positions (averting possible counterattacks), artillery regiments, command posts or supply lines. Because it is not necessary to deliver large quantities of the agent in a short period of time, a wide variety of weapons systems can be used.

A special form of persistent agents are thickened agents. These comprise a common agent mixed with thickeners to provide gelatinous, sticky agents. Primary targets for this kind of use include airfields, due to the increased persistency and difficulty of decontaminating affected areas.

Classes
Chemical weapons are agents that come in four categories: choking, blister, blood and nerve. The agents are organized into several categories according to the manner in which they affect the human body. The names and number of categories varies slightly from source to source, but in general, types of chemical warfare agents are as follows:

There are other chemicals used militarily that are not scheduled by the CWC, and thus are not controlled under the CWC treaties. These include:
 * Defoliants and herbicides that destroy vegetation, but are not immediately toxic or poisonous to human beings. Their use is classified as herbicidal warfare. Some batches of Agent Orange, for instance, used by the British during the Malayan Emergency and the United States during the Vietnam War, contained dioxins as manufacturing impurities. Dioxins, rather than Agent Orange itself, have long-term cancer effects and for causing genetic damage leading to serious birth defects.
 * Incendiary or explosive chemicals (such as napalm, extensively used by the United States during the Korean War and the Vietnam War, or dynamite) because their destructive effects are primarily due to fire or explosive force, and not direct chemical action. Their use is classified as conventional warfare.
 * Viruses, bacteria, or other organisms. Their use is classified as biological warfare. Toxins produced by living organisms are considered chemical weapons, although the boundary is blurry. Toxins are covered by the Biological Weapons Convention.

Designations
Most chemical weapons are assigned a one- to three-letter "NATO weapon designation" in addition to, or in place of, a common name. Binary munitions, in which precursors for chemical warfare agents are automatically mixed in shell to produce the agent just prior to its use, are indicated by a "-2" following the agent's designation (for example, GB-2 and VX-2).

Some examples are given below:

Delivery
The most important factor in the effectiveness of chemical weapons is the efficiency of its delivery, or dissemination, to a target. The most common techniques include munitions (such as bombs, projectiles, warheads) that allow dissemination at a distance and spray tanks which disseminate from low-flying aircraft. Developments in the techniques of filling and storage of munitions have also been important.

Although there have been many advances in chemical weapon delivery since World War I, it is still difficult to achieve effective dispersion. The dissemination is highly dependent on atmospheric conditions because many chemical agents act in gaseous form. Thus, weather observations and forecasting are essential to optimize weapon delivery and reduce the risk of injuring friendly forces.

Dispersion
Dispersion is placing the chemical agent upon or adjacent to a target immediately before dissemination, so that the material is most efficiently used. Dispersion is the simplest technique of delivering an agent to its target. The most common techniques are munitions, bombs, projectiles, spray tanks and warheads.

World War I saw the earliest implementation of this technique. The actual first chemical ammunition was the French 26 mm cartouche suffocante rifle grenade, fired from a flare carbine. It contained 35g of the tear-producer ethyl bromoacetate, and was used in autumn 1914 – with little effect on the Germans.

The German military contrarily tried to increase the effect of 10.5 cm shrapnel shells by adding an irritant – dianisidine chlorosulfonate. Its use against the British at Neuve Chapelle in October 1914 went unnoticed by them. Hans Tappen, a chemist in the Heavy Artillery Department of the War Ministry, suggested to his brother, the Chief of the Operations Branch at German General Headquarters, the use of the tear-gases benzyl bromide or xylyl bromide.

Shells were tested successfully at the Wahn artillery range near Cologne on January 9, 1915, and an order was placed for 15 cm howitzer shells, designated 'T-shells' after Tappen. A shortage of shells limited the first use against the Russians at the Battle of Bolimów on January 31, 1915; the liquid failed to vaporize in the cold weather, and again the experiment went unnoticed by the Allies.

The first effective use were when the German forces at the Second Battle of Ypres simply opened cylinders of chlorine and allowed the wind to carry the gas across enemy lines. While simple, this technique had numerous disadvantages. Moving large numbers of heavy gas cylinders to the front-line positions from where the gas would be released was a lengthy and difficult logistical task. Stockpiles of cylinders had to be stored at the front line, posing a great risk if hit by artillery shells. Gas delivery depended greatly on wind speed and direction. If the wind was fickle, as at the Battle of Loos, the gas could blow back, causing friendly casualties.

Gas clouds gave plenty of warning, allowing the enemy time to protect themselves, though many soldiers found the sight of a creeping gas cloud unnerving. This made the gas doubly effective, as, in addition to damaging the enemy physically, it also had a psychological effect on the intended victims.

Another disadvantage was that gas clouds had limited penetration, capable only of affecting the front-line trenches before dissipating. Although it produced limited results in World War I, this technique shows how simple chemical weapon dissemination can be.

Shortly after this "open canister" dissemination, French forces developed a technique for delivery of phosgene in a non-explosive artillery shell. This technique overcame many of the risks of dealing with gas in cylinders. First, gas shells were independent of the wind and increased the effective range of gas, making any target within reach of guns vulnerable. Second, gas shells could be delivered without warning, especially the clear, nearly odorless phosgene—there are numerous accounts of gas shells, landing with a "plop" rather than exploding, being initially dismissed as dud high explosive or shrapnel shells, giving the gas time to work before the soldiers were alerted and took precautions.

The major drawback of artillery delivery was the difficulty of achieving a killing concentration. Each shell had a small gas payload and an area would have to be subjected to saturation bombardment to produce a cloud to match cylinder delivery. A British solution to the problem was the Livens Projector. This was effectively a large-bore mortar, dug into the ground that used the gas cylinders themselves as projectiles – firing a 14 kg cylinder up to 1500 m. This combined the gas volume of cylinders with the range of artillery.

Over the years, there were some refinements in this technique. In the 1950s and early 1960s, chemical artillery rockets and cluster bombs contained a multitude of submunitions, so that a large number of small clouds of the chemical agent would form directly on the target.

Thermal dissemination
Thermal dissemination is the use of explosives or pyrotechnics to deliver chemical agents. This technique, developed in the 1920s, was a major improvement over earlier dispersal techniques, in that it allowed significant quantities of an agent to be disseminated over a considerable distance. Thermal dissemination remains the principal method of disseminating chemical agents today.

Most thermal dissemination devices consist of a bomb or projectile shell that contains a chemical agent and a central "burster" charge; when the burster detonates, the agent is expelled laterally.

Thermal dissemination devices, though common, are not particularly efficient. First, a percentage of the agent is lost by incineration in the initial blast and by being forced onto the ground. Second, the sizes of the particles vary greatly because explosive dissemination produces a mixture of liquid droplets of variable and difficult to control sizes.

The efficacy of thermal detonation is greatly limited by the flammability of some agents. For flammable aerosols, the cloud is sometimes totally or partially ignited by the disseminating explosion in a phenomenon called flashing. Explosively disseminated VX will ignite roughly one third of the time. Despite a great deal of study, flashing is still not fully understood, and a solution to the problem would be a major technological advance.

Despite the limitations of central bursters, most nations use this method in the early stages of chemical weapon development, in part because standard munitions can be adapted to carry the agents.

Aerodynamic dissemination
Aerodynamic dissemination is the non-explosive delivery of a chemical agent from an aircraft, allowing aerodynamic stress to disseminate the agent. This technique is the most recent major development in chemical agent dissemination, originating in the mid-1960s.

This technique eliminates many of the limitations of thermal dissemination by eliminating the flashing effect and theoretically allowing precise control of particle size. In actuality, the altitude of dissemination, wind direction and velocity, and the direction and velocity of the aircraft greatly influence particle size. There are other drawbacks as well; ideal deployment requires precise knowledge of aerodynamics and fluid dynamics, and because the agent must usually be dispersed within the boundary layer (less than 200 – above the ground), it puts pilots at risk.

Significant research is still being applied toward this technique. For example, by modifying the properties of the liquid, its breakup when subjected to aerodynamic stress can be controlled and an idealized particle distribution achieved, even at supersonic speed. Additionally, advances in fluid dynamics, computer modeling, and weather forecasting allow an ideal direction, speed, and altitude to be calculated, such that warfare agent of a predetermined particle size can predictably and reliably hit a target.

Protection against chemical warfare
Ideal protection begins with nonproliferation treaties such as the CWC, and detecting, very early, the signatures of someone building a chemical weapons capability. These include a wide range of intelligence disciplines, such as economic analysis of exports of dual-use chemicals and equipment, human intelligence (HUMINT) such as diplomatic, refugee, and agent reports; photography from satellites, aircraft and drones (IMINT); examination of captured equipment (TECHINT); communications intercepts (COMINT); and detection of chemical manufacturing and chemical agents themselves (MASINT).

If all the preventive measures fail and there is a clear and present danger, then there is a need for detection of chemical attacks, collective protection,  and decontamination. Since industrial accidents can cause dangerous chemical releases (e.g., the Bhopal disaster), these activities are things that civilian, as well as military, organizations must be prepared to carry out. In civilian situations in developed countries, these are duties of HAZMAT organizations, which most commonly are part of fire departments.

Detection has been referred to above, as a technical MASINT discipline; specific military procedures, which are usually the model for civilian procedures, depend on the equipment, expertise, and personnel available. When chemical agents are detected, an alarm needs to sound, with specific warnings over emergency broadcasts and the like. There may be a warning to expect an attack.

If, for example, the captain of a US Navy ship believes there is a serious threat of chemical, biological, or radiological attack, the crew may be ordered to set Circle William, which means closing all openings to outside air, running breathing air through filters, and possibly starting a system that continually washes down the exterior surfaces. Civilian authorities dealing with an attack or a toxic chemical accident will invoke the Incident Command System, or local equivalent, to coordinate defensive measures.

Individual protection starts with a gas mask and, depending on the nature of the threat, through various levels of protective clothing up to a complete chemical-resistant suit with a self-contained air supply. The US military defines various levels of MOPP (mission-oriented protective posture) from mask to full chemical resistant suits; Hazmat suits are the civilian equivalent, but go farther to include a fully independent air supply, rather than the filters of a gas mask.

Collective protection allows continued functioning of groups of people in buildings or shelters, the latter which may be fixed, mobile, or improvised. With ordinary buildings, this may be as basic as plastic sheeting and tape, although if the protection needs to be continued for any appreciable length of time, there will need to be an air supply, typically an enhanced gas mask.

Decontamination
Decontamination varies with the particular chemical agent used. Some nonpersistent agents, including most pulmonary agents (chlorine, phosgene, and so on), blood gases, and nonpersistent nerve gases (e.g., GB), will dissipate from open areas, although powerful exhaust fans may be needed to clear out buildings where they have accumulated.

In some cases, it might be necessary to neutralize them chemically, as with ammonia as a neutralizer for hydrogen cyanide or chlorine. Riot control agents such as CS will dissipate in an open area, but things contaminated with CS powder need to be aired out, washed by people wearing protective gear, or safely discarded.

Mass decontamination is a less common requirement for people than equipment, since people may be immediately affected and treatment is the action required. It is a requirement when people have been contaminated with persistent agents. Treatment and decontamination may need to be simultaneous, with the medical personnel protecting themselves so they can function.

There may need to be immediate intervention to prevent death, such as injection of atropine for nerve agents. Decontamination is especially important for people contaminated with persistent agents; many of the fatalities after the explosion of a WWII US ammunition ship carrying sulfur mustard, in the harbor of Bari, Italy, after a German bombing on December 2, 1943, came when rescue workers, not knowing of the contamination, bundled cold, wet seamen in tight-fitting blankets.

For decontaminating equipment and buildings exposed to persistent agents, such as blister agents, VX or other agents made persistent by mixing with a thickener, special equipment and materials might be needed. Some type of neutralizing agent will be needed; e.g. in the form of a spraying device with neutralizing agents such as Chlorine, Fichlor, strong alkaline solutions or enzymes. In other cases, a specific chemical decontaminant will be required.

Sociopolitical climate
There are many instances of the use of chemical weapons in battles documented in Greek and Roman historical texts; the earliest example was the deliberate poisoning of Kirrha's water supply with hellebore in the First Sacred War, Greece, about 590 BC.

One of the earliest reactions to the use of chemical agents was from Rome. Struggling to defend themselves from the Roman legions, Germanic tribes poisoned the wells of their enemies, with Roman jurists having been recorded as declaring "armis bella non venenis geri", meaning "war is fought with weapons, not with poisons." Yet the Romans themselves resorted to poisoning wells of besieged cities in Anatolia in the 2nd century BCE.

Before 1915 the use of poisonous chemicals in battle was typically the result of local initiative, and not the result of an active government chemical weapons program. There are many reports of the isolated use of chemical agents in individual battles or sieges, but there was no true tradition of their use outside of incendiaries and smoke. Despite this tendency, there have been several attempts to initiate large-scale implementation of poison gas in several wars, but with the notable exception of World War I, the responsible authorities generally rejected the proposals for ethical reasons or fears of retaliation.

For example, in 1854 Lyon Playfair (later 1st Baron Playfair, GCB, PC, FRS (1818–1898), a British chemist, proposed using a cacodyl cyanide-filled artillery shell against enemy ships during the Crimean War. The British Ordnance Department rejected the proposal as "as bad a mode of warfare as poisoning the wells of the enemy."

Efforts to eradicate chemical weapons

 * August 27, 1874: The Brussels Declaration Concerning the Laws and Customs of War is signed, specifically forbidding the "employment of poison or poisoned weapons", although the treaty was not adopted by any nation whatsoever and it never went into effect.
 * September 4, 1900: The First Hague Convention, which includes a declaration banning the "use of projectiles the object of which is the diffusion of asphyxiating or deleterious gases," enters into force.
 * January 26, 1910: The Second Hague Convention enters into force, prohibiting the use of "poison or poisoned weapons" in warfare.
 * February 6, 1922: After World War I, the Washington Arms Conference Treaty prohibited the use of asphyxiating, poisonous or other gases. It was signed by the United States, Britain, Japan, France, and Italy, but France objected to other provisions in the treaty and it never went into effect.
 * February 8, 1928: The Geneva Protocol enters into force, prohibiting the use of "asphyxiating, poisonous or other gases, and of all analogous liquids, materials or devices" and "bacteriological methods of warfare".

Chemical weapon proliferation
Despite numerous efforts to reduce or eliminate them, some nations continue to research and/or stockpile chemical warfare agents.

In 1997, future US Vice President Dick Cheney opposed the signing ratification of a treaty banning the use of chemical weapons, a recently unearthed letter shows. In a letter dated April 8, 1997, then Halliburton-CEO Cheney told Sen. Jesse Helms, the chairman of the Senate Foreign Relations Committee, that it would be a mistake for America to join the convention. "Those nations most likely to comply with the Chemical Weapons Convention are not likely to ever constitute a military threat to the United States. The governments we should be concerned about are likely to cheat on the CWC, even if they do participate," reads the letter, published by the Federation of American Scientists.

The CWC was ratified by the Senate that same month. In the following years, Albania, Libya, Russia, the United States, and India declared over 71,000 metric tons of chemical weapon stockpiles, and destroyed a third of them. Under the terms of the agreement, the United States and Russia agreed to eliminate the rest of their supplies of chemical weapons by 2012, but ended up taking far longer to do so as shown in the previous and following section of this article.

India
In June 1997, India declared that it had a stockpile of 1044 tons of sulphur mustard in its possession. India's declaration of its stockpile came after its entry into the Chemical Weapons Convention, that created the Organisation for the Prohibition of Chemical Weapons, and on January 14, 1993, India became one of the original signatories to the Chemical Weapons Convention. By 2005, from among six nations that had declared their possession of chemical weapons, India was the only country to meet its deadline for chemical weapons destruction and for inspection of its facilities by the Organisation for the Prohibition of Chemical Weapons. By 2006, India had destroyed more than 75 percent of its chemical weapons and material stockpile and was granted an extension to complete a 100 percent destruction of its stocks by April 2009. On May 14, 2009, India informed the United Nations that it has completely destroyed its stockpile of chemical weapons.

Iraq
The Director-General of the Organisation for the Prohibition of Chemical Weapons, Ambassador Rogelio Pfirter, welcomed Iraq's decision to join the OPCW as a significant step to strengthening global and regional efforts to prevent the spread and use of chemical weapons. The OPCW announced "The government of Iraq has deposited its instrument of accession to the Chemical Weapons Convention with the Secretary General of the United Nations and within 30 days, on 12 February 2009, will become the 186th State Party to the Convention". Iraq has also declared stockpiles of chemical weapons, and because of their recent accession is the only State Party exempted from the destruction time-line.

Japan
During the Second Sino-Japanese War (1937–1945) Japan stored chemical weapons on the territory of mainland China. The weapon stock mostly containing sulfur mustard-lewisite mixture. The weapons are classified as abandoned chemical weapons under the Chemical Weapons Convention, and from September 2010 Japan has started their destruction in Nanjing using mobile destruction facilities in order to do so.

Russia
Russia signed into the Chemical Weapons Convention on January 13, 1993, and ratified it on November 5, 1995. Declaring an arsenal of 39,967 tons of chemical weapons in 1997, by far the largest arsenal, consisting of blister agents: Lewisite, Sulfur mustard, Lewisite-mustard mix, and nerve agents: Sarin, Soman, and VX. Russia met its treaty obligations by destroying 1 percent of its chemical agents by the 2002 deadline set out by the Chemical Weapons Convention, but requested an extension on the deadlines of 2004 and 2007 due to technical, financial, and environmental challenges of chemical disposal. Since, Russia has received help from other countries such as Canada which donated C$100,000, plus a further C$100,000 already donated, to the Russian Chemical Weapons Destruction Program. This money will be used to complete work at Shchuch'ye and support the construction of a chemical weapons destruction facility at Kizner (Russia), where the destruction of nearly 5,700 tons of nerve agent, stored in approximately 2 million artillery shells and munitions, will be undertaken. Canadian funds are also being used for the operation of a Green Cross Public Outreach Office, to keep the civilian population informed on the progress made in chemical weapons destruction activities.

As of July 2011, Russia has destroyed 48 percent (18,241 tons) of its stockpile at destruction facilities located in Gorny (Saratov Oblast) and Kambarka (Udmurt Republic) – where operations have finished – and Schuch'ye (Kurgan Oblast), Maradykovsky (Kirov Oblast), Leonidovka (Penza Oblast) whilst installations are under construction in Pochep (Bryansk Oblast) and Kizner (Udmurt Republic). As August 2013, 76 percent (30,500 tons) were destroyed, and Russia leaves the Cooperative Threat Reduction (CTR) Program, which partially funded chemical weapons destruction.

In September 2017, OPCW announced that Russia had destroyed its entire chemical weapons stockpile.

United States
On November 25, 1969, President Richard Nixon unilaterally renounced the offensive use of biological and toxic weapons, but the U.S. continued to maintain an offensive chemical weapons program.

From May 1964 to the early 1970s the U.S. participated in Operation CHASE, a United States Department of Defense program that aimed to dispose of chemical weapons by sinking ships laden with the weapons in the deep Atlantic. After the Marine Protection, Research, and Sanctuaries Act of 1972, Operation Chase was scrapped and safer disposal methods for chemical weapons were researched, with the U.S. destroying several thousand tons of sulfur mustard by incineration at the Rocky Mountain Arsenal, and nearly 4,200 tons of nerve agent by chemical neutralisation at Tooele Army Depot.

The U.S. began stockpile reductions in the 1980s with the removal of outdated munitions and destroying its entire stock of 3-Quinuclidinyl benzilate (BZ or Agent 15) at the beginning of 1988. In June 1990 the Johnston Atoll Chemical Agent Disposal System began destruction of chemical agents stored on the Johnston Atoll in the Pacific, seven years before the Chemical Weapons Treaty came into effect. In 1986 President Ronald Reagan made an agreement with German Chancellor Helmut Kohl to remove the U.S. stockpile of chemical weapons from Germany. In 1990, as part of Operation Steel Box, two ships were loaded with over 100,000 shells containing Sarin and VX were taken from the U.S. Army weapons storage depots such as Miesau and then-classified FSTS (Forward Storage / Transportation Sites) and transported from Bremerhaven, Germany to Johnston Atoll in the Pacific, a 46-day nonstop journey.

In the 1980s, Congress, at the urging of the Reagan administration, Congress provided funding for the manufacture of binary chemical weapons (sarin artillery shells) from 1987 until 1990, but this was halted after the U.S. and the Soviet Union entered into a bilateral agreement in June 1990. In the 1990 agreement, the U.S. and Soviet Union agreed to begin destroying their chemical weapons stockpiles before 1993 and to reduce them to no more than 5,000 agent tons each by the end of 2002. The agreement also provided for exchanges of data and inspections of sites to verify destruction. Following the collapse of the Soviet Union, the U.S.'s Nunn–Lugar Cooperative Threat Reduction program helped eliminate some of the chemical, biological and nuclear stockpiles of the former Soviet Union.

The United Nations Conference on Disarmament in Geneva in 1980 led to the development of the Chemical Weapons Convention (CWC), a multilateral treaty that prohibited the development, production, stockpiling, and use of chemical weapons, and required the elimination of existing stockpiles. The treaty expressly prohibited state parties from making reservations (unilateral caveats). During the Reagan administration and the George H. W. Bush administration, the U.S. participated in the negotiations toward the CWC. The CWC was concluded on September 3, 1992, and opened for signature on January 13, 1993. The U.S. became one of 87 original state parties to the CWC. President Bill Clinton submitted it to the U.S. Senate for ratification on November 23, 1993. Ratification was blocked in the Senate for years, largely as a result of opposition from Senator Jesse Helms, the chairman of the Senate Foreign Relations Committee. On April 24, 1997, the Senate gave its consent to ratification of the CWC by a 74–26 vote (satisfying the required two-thirds majority). The U.S. deposited its instrument of ratification at the United Nations on April 25, 1997, a few days before the CWC entered into force. The U.S. ratification allowed the U.S. to participate in the Organisation for the Prohibition of Chemical Weapons, the organization based in The Hague that oversees implementation of the CWC.

Upon U.S. ratification of the CWC, the U.S. declared a total of 29,918 tons of chemical weapons, and committed to destroying all of the U.S.'s chemical weapons and bulk agent. The U.S. was one of eight states to declare a stockpile of chemical weapons and to commit to their safe elimination. The U.S. committed in the CWC to destroy its entire chemical arsenal within 10 years of the entry into force (i.e., by April 29, 2007), However, at a 2012 conference, the parties to the CWC parties agreed to extend the U.S. deadline to 2023. By 2012, stockpiles had been eliminated at seven of the U.S.'s nine chemical weapons depots and 89.75% of the 1997 stockpile was destroyed. The depots were the Aberdeen Chemical Agent Disposal Facility, Anniston Chemical Disposal Facility, Johnston Atoll, Newport Chemical Agent Disposal Facility, Pine Bluff Chemical Disposal Facility, Tooele Chemical Disposal Facility, Umatilla Chemical Disposal Facility, and Deseret Chemical Depot. The U.S. closed each site after the completion of stockpile destruction. In 2019, the U.S. began to eliminate its chemical-weapon stockpile at the last of the nine U.S. chemical weapons storage facilities: the Blue Grass Army Depot in Kentucky. By May 2021, the U.S. destroyed all of its Category 2 and Category 3 chemical weapons and 96.52% of its Category 1 chemical weapons. The U.S. is scheduled to complete the elimination of all its chemical weapons by the September 2023 deadline. In July 2023 OPCW confirmed the last chemical munition of the U.S., and that the last chemical weapon from the stockpiles declared by all States Parties to the Chemical Weapons Convention was verified as destroyed.

The U.S. has maintained a "calculated ambiguity" policy that warns potential adversaries that a chemical or biological attack against the U.S. or its allies will prompt a "overwhelming and devastating" response. The policy deliberately leaves open the question of whether the U.S. would respond to a chemical attempt with nuclear retaliation. Commentators have noted that this policy gives policymakers more flexibility, at the possible cost of decreased strategic unpreparedness.

Herbicidal warfare
Although herbicidal warfare use chemical substances, its main purpose is to disrupt agricultural food production and/or to destroy plants which provide cover or concealment to the enemy.

The use of herbicides by the U.S. military during the Vietnam War has left tangible, long-term impacts upon the Vietnamese people and U.S. veterans of the war. The government of Vietnam says that around 24% of the forests of Southern Vietnam were defoliated and up to four million people in Vietnam were exposed to Agent Orange. They state that as many as three million people have developed illness because of Agent Orange while the Red Cross of Vietnam estimates that up to one million people were disabled or have health problems associated with Agent Orange. The United States government has described these figures as unreliable. During the war, the U.S. fought the North Vietnamese and their allies in Laos and Cambodia, dropping large quantities of Agent Orange in each of those countries. According on one estimate, the U.S. dropped 475,500 USgal of Agent Orange in Laos and 40,900 USgal in Cambodia. Because Laos and Cambodia were officially neutral during the Vietnam War, the U.S. attempted to keep secret its military involvement in these countries. The U.S. has stated that Agent Orange was not widely used and therefore hasn't offered assistance to affected Cambodians or Laotians, and limits benefits American veterans and CIA personnel who were stationed there.

Anti-livestock
During the Mau Mau Uprising in 1952, the poisonous latex of the African milk bush was used to kill cattle.

title: Chemical warfare