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Keratin

Keratin is one of a family of structural fibrous proteins also known as scleroproteins. Alpha-keratin (α-keratin) is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, and the outer layer of skin among vertebrates. Keratin also protects epithelial cells from damage or stress. Keratin is extremely insoluble in water and organic solvents. Keratin monomers assemble into bundles to form intermediate filaments, which are tough and form strong unmineralized epidermal appendages found in reptiles, birds, amphibians, and mammals. Excessive keratinization participate in fortification of certain tissues such as in horns of cattle and rhinos, and armadillos' osteoderm. The only other biological matter known to approximate the toughness of keratinized tissue is chitin. Keratin comes in two types, the primitive, softer forms found in all vertebrates and harder, derived forms found only among sauropsids (reptiles and birds).

Spider silk is classified as keratin, although production of the protein may have evolved independently of the process in vertebrates.

Examples of occurrence
Alpha-keratins (α-keratins) are found in all vertebrates. They form the hair (including wool), the outer layer of skin, horns, nails, claws and hooves of mammals, and the slime threads of hagfish. The baleen plates of filter-feeding whales are also made of keratin. Keratin filaments are abundant in keratinocytes in the hornified layer of the epidermis; these are proteins which have undergone keratinization. They are also present in epithelial cells in general. For example, mouse thymic epithelial cells react with antibodies for keratin 5, keratin 8, and keratin 14. These antibodies are used as fluorescent markers to distinguish subsets of mouse thymic epithelial cells in genetic studies of the thymus.

The harder beta-keratins (β-keratins) are found only in the sauropsids, that is all living reptiles and birds. They are found in the nails, scales, and claws of reptiles, in some reptile shells (Testudines, such as tortoise, turtle, terrapin), and in the feathers, beaks, and claws of birds. These keratins are formed primarily in beta sheets. However, beta sheets are also found in α-keratins. Recent scholarship has shown that sauropsid β-keratins are fundamentally different from α-keratins at a genetic and structural level. The new term corneous beta protein (CBP) has been proposed to avoid confusion with α-keratins.

Keratins (also described as cytokeratins) are polymers of type I and type II intermediate filaments that have been found only in chordates (vertebrates, amphioxi, urochordates). Nematodes and many other non-chordate animals seem to have only type VI intermediate filaments, fibers that structure the nucleus.

Genes
The human genome encodes 54 functional keratin genes, located in two clusters on chromosomes 12 and 17. This suggests that they originated from a series of gene duplications on these chromosomes.

The keratins include the following proteins of which KRT23, KRT24, KRT25, KRT26, KRT27, KRT28, KRT31, KRT32, KRT33A, KRT33B, KRT34, KRT35, KRT36, KRT37, KRT38, KRT39, KRT40, KRT71, KRT72, KRT73, KRT74, KRT75, KRT76, KRT77, KRT78, KRT79, KRT8, KRT80, KRT81, KRT82, KRT83, KRT84, KRT85 and KRT86 have been used to describe keratins past 20.

Protein structure
The first sequences of keratins were determined by Israel Hanukoglu and Elaine Fuchs (1982, 1983). These sequences revealed that there are two distinct but homologous keratin families, which were named type I and type II keratins. By analysis of the primary structures of these keratins and other intermediate filament proteins, Hanukoglu and Fuchs suggested a model in which keratins and intermediate filament proteins contain a central ~310 residue domain with four segments in α-helical conformation that are separated by three short linker segments predicted to be in beta-turn conformation. This model has been confirmed by the determination of the crystal structure of a helical domain of keratins.

Type 1 and 2 Keratins
The human genome has 54 functional annotated Keratin genes, 28 are in the Keratin type 1 family, and 26 are in the Keratin type 2 family.

Fibrous keratin molecules supercoil to form a very stable, left-handed superhelical motif to multimerise, forming filaments consisting of multiple copies of the keratin monomer.

The major force that keeps the coiled-coil structure is hydrophobic interactions between apolar residues along the keratins helical segments.

Limited interior space is the reason why the triple helix of the (unrelated) structural protein collagen, found in skin, cartilage and bone, likewise has a high percentage of glycine. The connective tissue protein elastin also has a high percentage of both glycine and alanine. Silk fibroin, considered a β-keratin, can have these two as 75–80% of the total, with 10–15% serine, with the rest having bulky side groups. The chains are antiparallel, with an alternating C → N orientation. A preponderance of amino acids with small, nonreactive side groups is characteristic of structural proteins, for which H-bonded close packing is more important than chemical specificity.

Disulfide bridges
In addition to intra- and intermolecular hydrogen bonds, the distinguishing feature of keratins is the presence of large amounts of the sulfur-containing amino acid cysteine, required for the disulfide bridges that confer additional strength and rigidity by permanent, thermally stable crosslinking —in much the same way that non-protein sulfur bridges stabilize vulcanized rubber. Human hair is approximately 14% cysteine. The pungent smells of burning hair and skin are due to the volatile sulfur compounds formed. Extensive disulfide bonding contributes to the insolubility of keratins, except in a small number of solvents such as dissociating or reducing agents. The more flexible and elastic keratins of hair have fewer interchain disulfide bridges than the keratins in mammalian fingernails, hooves and claws (homologous structures), which are harder and more like their analogs in other vertebrate classes. Hair and other α-keratins consist of α-helically coiled single protein strands (with regular intra-chain H-bonding), which are then further twisted into superhelical ropes that may be further coiled. The β-keratins of reptiles and birds have β-pleated sheets twisted together, then stabilized and hardened by disulfide bridges.

Thiolated polymers (=thiomers) can form disulfide bridges with cysteine substructures of keratins getting covalently attached to these proteins. Thiomers exhibit therefore high binding properties to keratins found in hair, on skin and on the surface of many cell types.

Filament formation
It has been proposed that keratins can be divided into 'hard' and 'soft' forms, or 'cytokeratins' and 'other keratins'. That model is now understood to be correct. A new nuclear addition in 2006 to describe keratins takes this into account.

Keratin filaments are intermediate filaments. Like all intermediate filaments, keratin proteins form filamentous polymers in a series of assembly steps beginning with dimerization; dimers assemble into tetramers and octamers and eventually, if the current hypothesis holds, into unit-length-filaments (ULF) capable of annealing end-to-end into long filaments.

Cornification
Cornification is the process of forming an epidermal barrier in stratified squamous epithelial tissue. At the cellular level, cornification is characterised by: Metabolism ceases, and the cells are almost completely filled by keratin. During the process of epithelial differentiation, cells become cornified as keratin protein is incorporated into longer keratin intermediate filaments. Eventually the nucleus and cytoplasmic organelles disappear, metabolism ceases and cells undergo a programmed death as they become fully keratinized. In many other cell types, such as cells of the dermis, keratin filaments and other intermediate filaments function as part of the cytoskeleton to mechanically stabilize the cell against physical stress. It does this through connections to desmosomes, cell–cell junctional plaques, and hemidesmosomes, cell-basement membrane adhesive structures.
 * production of keratin
 * production of small proline-rich (SPRR) proteins and transglutaminase which eventually form a cornified cell envelope beneath the plasma membrane
 * terminal differentiation
 * loss of nuclei and organelles, in the final stages of cornification

Cells in the epidermis contain a structural matrix of keratin, which makes this outermost layer of the skin almost waterproof, and along with collagen and elastin gives skin its strength. Rubbing and pressure cause thickening of the outer, cornified layer of the epidermis and form protective calluses, which are useful for athletes and on the fingertips of musicians who play stringed instruments. Keratinized epidermal cells are constantly shed and replaced.

These hard, integumentary structures are formed by intercellular cementing of fibers formed from the dead, cornified cells generated by specialized beds deep within the skin. Hair grows continuously and feathers molt and regenerate. The constituent proteins may be phylogenetically homologous but differ somewhat in chemical structure and supermolecular organization. The evolutionary relationships are complex and only partially known. Multiple genes have been identified for the β-keratins in feathers, and this is probably characteristic of all keratins.

Silk
The silk fibroins produced by insects and spiders are often classified as keratins, though it is unclear whether they are phylogenetically related to vertebrate keratins.

Silk found in insect pupae, and in spider webs and egg casings, also has twisted β-pleated sheets incorporated into fibers wound into larger supermolecular aggregates. The structure of the spinnerets on spiders' tails, and the contributions of their interior glands, provide remarkable control of fast extrusion. Spider silk is typically about 1 to 2 micrometers (μm) thick, compared with about 60 μm for human hair, and more for some mammals. The biologically and commercially useful properties of silk fibers depend on the organization of multiple adjacent protein chains into hard, crystalline regions of varying size, alternating with flexible, amorphous regions where the chains are randomly coiled. A somewhat analogous situation occurs with synthetic polymers such as nylon, developed as a silk substitute. Silk from the hornet cocoon contains doublets about 10 μm across, with cores and coating, and may be arranged in up to 10 layers, also in plaques of variable shape. Adult hornets also use silk as a glue, as do spiders.

Glue
Glues made from partially-hydrolysed keratin include hoof glue and horn glue.

Clinical significance
Abnormal growth of keratin can occur in a variety of conditions including keratosis, hyperkeratosis and keratoderma.

Mutations in keratin gene expression can lead to, among others:
 * Alopecia Areata
 * Epidermolysis bullosa simplex
 * Ichthyosis bullosa of Siemens
 * Epidermolytic hyperkeratosis
 * Steatocystoma multiplex
 * Keratosis pharyngis
 * Rhabdoid cell formation in Large cell lung carcinoma with rhabdoid phenotype

Several diseases, such as athlete's foot and ringworm, are caused by infectious fungi that feed on keratin.

Keratin is highly resistant to digestive acids if ingested. Cats regularly ingest hair as part of their grooming behavior, leading to the gradual formation of hairballs that may be expelled orally or excreted. In humans, trichophagia may lead to Rapunzel syndrome, an extremely rare but potentially fatal intestinal condition.

Diagnostic use
Keratin expression is helpful in determining epithelial origin in anaplastic cancers. Tumors that express keratin include carcinomas, thymomas, sarcomas and trophoblastic neoplasms. Furthermore, the precise expression-pattern of keratin subtypes allows prediction of the origin of the primary tumor when assessing metastases. For example, hepatocellular carcinomas typically express CK8 and CK18, and cholangiocarcinomas express CK7, CK8 and CK18, while metastases of colorectal carcinomas express CK20, but not CK7.

title: Keratin


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Lund Municipality

Lund Municipality (Lunds kommun) is a municipality in Scania County, southern Sweden. Its seat is the city of Lund.

As most municipalities in Sweden, the territory of municipality consists of many former local government units, united in a series of amalgamations. The number of original entities (as of 1863) is 22. At the time of the nationwide municipal reform of 1952 the number had been reduced to six. In 1967 the rural municipality Torn (itself created in 1952) was added to Lund. The City of Lund was made a unitary municipality in 1971 and amalgamated with Dalby, Genarp, Södra Sandby and Veberöd in 1974 completing the process. Since 2016, the municipality is subdivided into 16 districts for the purposes of population and land registration.

Dalby Söderskog, one of Sweden's national parks, is located within the municipality near Dalby. Municipal bird of Lund is Eurasian penduline tit.

Localities
There are nine urban areas in Lund Municipality:

Demographics
This is a demographic table based on Lund Municipality's electoral districts in the 2022 Swedish general election sourced from SVT's election platform, in turn taken from SCB official statistics.

In total there were 127,202 residents, including 93,503 Swedish citizens of voting age. 57.1% voted for the left coalition and 41.4% for the right coalition. This was in stark contrast to the rest of the Skåne Southern constituency, that was won by the right with a sizeable margin. Indicators are in percentage points except population totals and income.

Municipal council
In the 2018 municipal election, no bloc was able to gain control of the executive, a five-party minority coalition consisting of the four Alliance parties and local party FörNyaLund was formed as a result. Philip Sandberg of the Liberals heads the executive. The election results are presented in the table below. The turnout was 86.37%.

Twin towns — sister cities
The municipality is twinned with the following local government areas:

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

title: Lund Municipality


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Ballista

The ballista (Latin, from Greek βαλλίστρα ballistra and that from βάλλω ballō, "throw"), plural ballistae, sometimes called bolt thrower, was an ancient missile weapon that launched either bolts or stones at a distant target.

Developed from earlier Greek weapons, it relied upon different mechanics, using two levers with torsion springs instead of a tension prod (the bow part of a modern crossbow). The springs consisted of several loops of twisted skeins. Early versions projected heavy darts or spherical stone projectiles of various sizes for siege warfare. It developed into a smaller precision weapon, the scorpio, and possibly the polybolos.

Greek weapon
The early ballistae in Ancient Greece were developed from two weapons called oxybeles and gastraphetes. The gastraphetes ('belly-bow') was a handheld crossbow. It had a composite prod and was spanned by bracing the front end of the weapon against the ground while placing the end of a slider mechanism against the stomach. The operator would then walk forward to arm the weapon while a ratchet prevented it from shooting during loading. This produced a weapon that, it was claimed, could be operated by a person of average strength but which had a power that allowed it to be successfully used against armored troops. The oxybeles were a bigger and heavier construction employing a winch and were mounted on a tripod. It had a lower rate of fire and was used as a siege engine.

With the invention of torsion spring bundle technology, the first ballistae were built. The advantage of this new technology was the fast relaxation time of this system. Thus it was possible to shoot lighter projectiles with higher velocities over a longer distance. By contrast, the comparatively slow relaxation time of a tension machine such as the oxybeles meant that much less energy could be transferred to light projectiles, limiting the effective range of the weapon.

The earliest form of the ballista is thought to have been developed for Dionysius of Syracuse, c. 400 BC.

The Greek ballista was a siege weapon. All components that were not made of wood were transported in the baggage train. It would be assembled with local wood, if necessary. Some were positioned inside large, armored, mobile siege towers or even on the edge of a battlefield. For all of the tactical advantages offered, it was only under Philip II of Macedon, and even more so under his son Alexander, that the ballista began to develop and gain recognition as both a siege engine and field artillery. Historical accounts, for instance, cited that Philip II employed a group of engineers within his army to design and build catapults for his military campaigns. There is even a claim that it was Philip II with his team of engineers who invented the ballista after improving Dionysius's device, which was merely an oversized slingshot. It was further perfected by Alexander, whose own team of engineers introduced innovations such as the idea of using springs made from tightly strung coils of rope instead of a bow to achieve more energy and power when throwing projectiles. Polybius reported about the usage of smaller, more portable ballistae, called scorpions, during the Second Punic War.

Ballistae could be easily modified to shoot both spherical and shaft projectiles, allowing their crews to adapt quickly to prevailing battlefield situations in real time.

As the role of battlefield artillery became more sophisticated, a universal joint (which was invented just for this function) was integrated into the ballista's stand, allowing the operators to alter the trajectory and firing direction of the ballista as required without a lengthy disassembly of the machine.

Roman weaponry

After the absorption of the Ancient Greek city-states into the Roman Republic in 146 BC, the highly advanced Greek technology began to spread across many areas of Roman influence. This included the great military machine advances the Greeks had made (most notably by Dionysus of Syracuse), as well as all the scientific, mathematical, political and artistic developments.

The Romans adopted the torsion-powered ballista, which had by now spread to several cities around the Mediterranean, all of which became Roman spoils of war, including one from Pergamon, which was depicted among a pile of trophy weapons in relief on a balustrade.

The torsion ballista, developed by Alexander, was a far more complicated weapon than its predecessor and the Romans developed it even further, especially into much smaller versions, that could be easily carried.

Early Roman ballistae
The early Roman ballistae were made of wood, and held together with iron plates around the frames and iron nails in the stand. The main stand had a slider on the top, into which were loaded the bolts or stone shot. Attached to this, at the back, was a pair of 'winches' and a 'claw', used to ratchet the bowstring back to the armed firing position.

The slider passed through the field frames of the weapon, in which were located the torsion springs (rope made of animal sinew), which were twisted around the bow arms, which in turn, were attached to the bowstring.

Drawing the bowstring back with the winches twisted the already taut springs, storing the energy to fire the projectiles. The bronze or iron caps, which secured the torsion bundles were adjustable by means of pins and peripheral holes, which allowed the weapon to be tuned for symmetrical power and for changing weather conditions.

The ballista was a highly accurate weapon (there are many accounts of single soldiers being picked off by ballistarii), but some design aspects meant it could compromise its accuracy for range. The maximum range was over 500 yd, but the effective combat range for many targets was far shorter.

The Romans continued the development of the ballista, and it became a highly prized and valued weapon in the army of the Roman Empire.

It was used, just before the start of the Empire, by Julius Caesar during his conquest of Gaul and on both of his campaigns in subduing Britain.

First invasion of Britain
The first of Caesar's invasions of Britain took place in 55 BC, after a rapid and successful initial conquest of Gaul, in part as an expedition, and more practical to try to put an end to the reinforcements sent by the native Britons to fight the Romans in Gaul.

A total of eighty means of transport, carrying two legions, attempted to land on the British shore, only to be driven back by the many British warriors assembled along the shoreline. The ships had to unload their troops on the beach, as it was the only one suitable for many miles, yet the massed ranks of British charioteers and javeliners were making it difficult.

"Seeing this, Caesar ordered the warships – which were swifter and easier to handle than the transports, and likely to impress the natives more by their unfamiliar appearance – to be removed a short distance from the others, and then be rowed hard and run ashore on the enemy’s right flank, from which position men on deck could use the slings, bows, and artillery to drive them back. This maneuver was highly successful. Scared by the strange shape of the warships, the motion of the oars, and the unfamiliar machines, the natives halted and retreated. (Caesar, The Conquest of Gaul, p.99)"

Siege of Alesia
In Gaul, the stronghold of Alesia was under a Roman siege in 52 BC, and was completely surrounded by a Roman fortification including a wooden palisade and towers. As was standard siege technique at the time, small ballistae were placed in the towers with other troops armed with bows or slings. The use of the ballista in the Roman siege strategy was also demonstrated in the case of the Siege of Masada.

Ballistae in the Roman Empire
During the conquest of the Empire, the ballista proved its worth many times in sieges and battles, both at sea and on land. It is from the time of the Roman Empire that many of the archaeological finds of ballistae date. Accounts by the finders, including technical manuals and journals, are used today by archaeologists to reconstruct these weapons.

After Julius Caesar, the ballista was a permanent fixture in the Roman army and, over time, modifications and improvements were made by successive engineers. This included replacing the remaining wooden parts of the machine with metal, creating a much smaller, lighter and more powerful machine than the wooden version, which required less maintenance (though the vital torsion springs were still vulnerable to the strain). The largest ballistae of the 4th century could throw a dart further than 1200 yards (1,100 m). The weapon was named ballista fulminalis in De rebus bellicis: "From this ballista, darts were projected not only in great number but also at a large size over a considerable distance, such as across the width of the Danube River." Ballistae were not only used in laying siege: after AD 350, at least 22 semi-circular towers were erected around the walls of Londinium (London) to provide platforms for permanently mounted defensive devices.

Eastern Roman Empire
During the 6th century, Procopius described the effects of this weapon: "But Belisarius placed upon the towers engines which they call 'ballistae'. Now these engines have the form of a bow, but on the under side of them a grooved wooden shaft projects; this shaft is so fitted to the bow that it is free to move, and rests upon a straight iron bed. So when men wish to shoot at the enemy with this, they make the parts of the bow which form the ends bend toward one another by means of a short rope fastened to them, and they place in the grooved shaft the arrow, which is about one half the length of the ordinary missiles which they shoot from bows, but about four times as wide...but the missile is discharged from the shaft, and with such force that it attains the distance of not less than two bow-shots, and that, when it hits a tree or a rock, it pierces it easily. Such is the engine which bears this name, being so called because it shoots with very great force..."

The missiles were able to penetrate body-armour:

"And at the Salarian Gate a Goth of goodly stature and a capable warrior, wearing a corselet and having a helmet on his head, a man who was of no mean station in the Gothic nation, refused to remain in the ranks with his comrades, but stood by a tree and kept shooting many missiles at the parapet. But this man by some chance was hit by a missile from an engine which was on a tower at his left. And passing through the corselet and the body of the man, the missile sank more than half its length into the tree, and pinning him to the spot where it entered the tree, it suspended him there a corpse."

Carroballista
The carroballista was a cart-mounted version of the weapon. There were probably different models of ballista under the cheiroballistra class, at least two different two-wheeled models and one model with four wheels. Their probable size was roughly 1.47 m width, i.e., 5 Roman feet. The cart system and structure gave it a great deal of flexibility and capability as a battlefield weapon, since the increased maneuverability allowed it to be moved with the flow of the battle. This weapon features several times on Trajan's Column.

Polybolos
It has been speculated that the Roman military may have also fielded a 'repeating' ballista, also known as a polybolos. Reconstruction and trials of such a weapon carried out in a BBC documentary, What the Romans Did For Us, showed that they "were able to shoot eleven bolts a minute, which is almost four times the rate at which an ordinary ballista can be operated". However, no example of such a weapon has been found by archaeologists.

Cheiroballistra and manuballista
The cheiroballistra and the manuballista are held by many archaeologists to be the same weapon. The difference in name may be attributable to the different languages spoken in the Empire. Latin remained the official language in the Western Empire, but the Eastern Empire predominantly used Greek, which added an extra 'r' to the word ballista.

The manuballista was a handheld version of the traditional ballista. This new version was made entirely of iron, which conferred greater power to the weapon, since it was smaller, and less iron (an expensive material before the 19th century), was used in its production. It was not the ancient gastraphetes, but the Roman weapon. However, the same physical limitations applied as with the gastraphetes.

Archaeology and the Roman ballista
Archaeology, and in particular experimental archaeology has been influential on this subject. Although several ancient authors (such as Vegetius) wrote very detailed technical treatises, providing us with all the information necessary to reconstruct the weapons, all their measurements were in their native language and therefore highly difficult to translate.

Attempts to reconstruct these ancient weapons began at the end of the 19th century, based on rough translations of ancient authors. It was only during the 20th century, however, that many of the reconstructions began to make any sense as a weapon. By bringing in modern engineers, progress was made with the ancient systems of measurement. By redesigning the reconstructions using the new information, archaeologists in that specialty were able to recognise certain finds from Roman military sites, and identify them as ballistae. The information gained from the excavations was fed into the next generation of reconstructions and so on.

Sites across the empire have yielded information on ballistae, from Spain (the Ampurias Catapult), to Italy (the Cremona Battleshield, which proved that the weapons had decorative metal plates to shield the operators), to Iraq (the Hatra Machine) and even Scotland (Burnswark siege tactics training camp), and many other sites between.

The most influential archaeologists in this area have been Peter Connolly and Eric Marsden, who have not only written extensively on the subject but have also made many reconstructions themselves and have refined the designs over many years of work.

Middle Ages
With the decline of the Roman Empire, resources to build and maintain these complex machines became very scarce, so the ballista was likely supplanted initially by the simpler and cheaper onager and the more efficient springald.

However, while it remained less and less popular as more efficient siege engines such as the trebuchet and the mangonel became widespread, the Ballista still retained some use in Medieval Siege Warfare, especially by city and castle garrisons, until it became finally extinguished by the more convenient medieval canons, already omnipresent in all major European Catholic cities by the first half of the 14th century.

The Littere Wallie records the existence of 4 "balistas ad turrimi" at "Duluithelan" [Dolwyddelan] Castle in 1280, one "balistam de tur" at "Rothelano"[Rhuddlan] castle and one "magnam ballistam" at "Bere Blada" Castle [Castell y Bere?] in 1286. These all being held under the authority of the English Crown.

In remote and seemingly "savage" places like Ireland, however, where cannons were rare and personal firearms were almost non-existent, ballistae had recorded use well into late 15th century.

While not a direct descendant mechanically, the concept and naming continues on as arbalest crossbows (arcus 'bow' + ballista).

title: Ballista


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Trebuchet

A trebuchet (trébuchet) is a type of catapult that uses a rotating arm with a sling attached to the tip to launch a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights and further distances than that of a traditional catapult.

There are two main types of trebuchet. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. It first appeared in China by the 4th century BC. It spread westward, possibly by the Avars, and was adopted by the Byzantines, Persians, Arabs, and other neighboring peoples by the sixth to seventh centuries AD.

The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century.

Etymology and terminology
The numerous forms of the word that appeared during the 13th century, including trabocco, tribok, tribuclietta, and trubechetum, have obscured the origin of the term. In Arabic the counterweight trebuchet was called manjaniq maghribi or majaniq ifranji. In China it was called the húihúi pào (Muslim trebuchet).

The English word trebuchet is first mentioned in the 14th century (13th century in Anglo-Latin) as "medieval stone-throwing engine of war". It is borrowed from (Old) French trebuchet (now trébuchet).

The French word is from the verbal root of trebucher (now trébucher) : trebuch- + diminutive noun suffix -et, trebucher (10th century) meant "to overthrow, to bring down", then and now "to stumble", maybe earlier "to rock" or "to tilt". It is a compound of (Old) French tre(s)-, variant form tra- (now tré- / tra-) from Latin trans expressing "displacement" in that case + Old French buc "trunk of the body, bulk", itself from Old Low Franconian *būk- "belly" similar to Old High German buh, German Bauch "belly".

The earliest appearance of the term "trebuchet" in French dates to the late 12th century and the first attestations of trebuchet as a siege weapon are from around the year 1200. The 1174-77 edition of Roman de Renart, an epic about Renard the Fox, describes it as a "trap whose trigger mechanism consists of an assembly of balanced logs" (understood as animal trap by 1375) while the ca. 1200 edition describes it as a "war engine that throws stones to break down walls". The word trabuchellus appeared alongside manganum and prederia in a document in Vicenza on April 6, 1189. Trabucha is found a decade later with predariae at the siege of Castelnuovo Bocca d'Adda in an account by Iohannes Codagnellus. It is unclear, however, whether these referred to counterweight trebuchets. Codagnellus did not specify a specific type of engine with the term and even implied that they were "fairly light in subsequent references". Only in the late 1210s do variations of "trebuchet" in sources, described as increasingly powerful machines or utilizing different components, identify more closely with the counterweight trebuchet. Other terms, such as machina maior/magna, might have also referred to counterweight trebuchets.

Traction trebuchet and counterweight trebuchet are modern terms (retronyms), not used by contemporary users of the weapons. The term traction trebuchet was created mainly to distinguish this type of weapon from the onager, a torsion powered catapult that is often conflated in contemporary sources with the mangonel, which was used as a generic term for any medieval stone throwing artillery. Both the traction and counterweight trebuchets have been called mangonel at one point or another. Confusion between the onager, mangonel, trebuchet, and other catapult types in contemporary terminology has led some historians today to use the more precise traction trebuchet instead, with counterweight trebuchet used to distinguish what was before called simply a trebuchet. Some modern historians use mangonel to mean exclusively traction trebuchets, while others call traction trebuchets traction mangonels and counterweight trebuchets counterweight mangonels.

Basic design

The trebuchet is a compound machine that makes use of the mechanical advantage of a lever to throw a projectile. They are typically large constructions, with the length of the beam as much as 15 m, with some purported to be even larger.

A trebuchet consists primarily of a long beam attached by an axle suspended high above the ground by a stout frame and base, such that the beam can rotate vertically through a wide arc (typically over 180°). A sling is attached to one end of the beam to hold the projectile. The projectile is thrown when the beam is quickly rotated by applying force to the opposite end of the beam. The mechanical advantage is primarily obtained by having the projectile section of the beam much longer than the opposite section where the force is applied – usually four to six times longer.

The difference between counterweight and traction trebuchets is what force they use. Counterweight trebuchets use gravity; potential energy is stored by slowly raising an extremely heavy box (typically filled with stones, sand, or lead) attached to the shorter end of the beam (typically on a hinged connection), and releasing it on command.

Traction trebuchets use human power; on command, men pull ropes attached to the shorter end of the trebuchet beam. The difficulties of coordinating the pull of many men together repeatedly and predictably makes counterweight trebuchets preferable for the larger machines, though they are more complicated to engineer. The trebuchet had further modifications to allow an increase to its range, by creating a slot for the sling and projectile to sit underneath the trebuchet, enabling the sling to be lengthened and thus extending the range, an alteration in the trajectory, or the release point to be changed. Further increasing their complexity is that either winches or treadwheels, aided by block and tackle, are typically required to raise the more massive counterweights. So while counterweight trebuchets require significantly fewer men to operate than traction trebuchets, they require significantly more time to reload. In a long siege, reload time may not be a critical concern.

When the trebuchet is operated, the force causes rotational acceleration of the beam around the axle (the fulcrum of the lever). These factors multiply the acceleration transmitted to the throwing portion of the beam and its attached sling. The sling starts rotating with the beam, but rotates farther (typically about 360°) and therefore faster, transmitting this increased speed to the projectile. The length of the sling increases the mechanical advantage, and also changes the trajectory so that, at the time of release from the sling, the projectile is traveling in the desired speed and angle to give it the range to hit the target. Adjusting the sling's release point is the primary means of fine-tuning the range, as the rest of the trebuchet's actions are difficult to adjust after construction.

The rotation speed of the throwing beam increases smoothly, starting slow but building up quickly. After the projectile is released, the arm continues to rotate, allowed to smoothly slow down on its own accord and come to rest at the end of the rotation. This is unlike the violent sudden stop inherent in the action of other catapult designs such as the onager, which must absorb most of the launching energy into their own frame, and must be heavily built and reinforced as a result. This key difference makes the trebuchet much more durable, allowing for larger and more powerful machines.

A trebuchet projectile can be almost anything, even debris, rotting carcasses, or incendiaries, but is typically a large stone. Dense stone, or even metal, specially worked to be round and smooth, gives the best range and predictability. When attempting to breach enemy walls, it is important to use materials that will not shatter on impact; projectiles were sometimes brought from distant quarries to get the desired properties.

Traction trebuchet
The traction trebuchet, also referred to as a mangonel in some sources, originated in ancient China.

The first recorded use of traction trebuchets was in ancient China. They were probably used by the Mohists as early as 4th century BC; descriptions can be found in the Mozi (compiled in the 4th century BC). According to the Mozi, the traction trebuchet was 17 ft high with 4 ft buried below ground, the fulcrum attached was constructed from the wheels of a cart, the throwing arm was 30–35 ft long with three quarters above the pivot and a quarter below to which the ropes are attached, and the sling 2.8 ft long. The range given for projectiles are 300 ft, 180 ft, and 120 ft. They were used as defensive weapons stationed on walls and sometimes hurled hollowed-out logs filled with burning charcoal to destroy enemy siege works. By the 1st century AD, commentators were interpreting other passages in texts such as the Zuo zhuan and Classic of Poetry as references to the traction trebuchet: "the guai is 'a great arm of wood on which a stone is laid, and this by means of a device [ji] is shot off and so strikes down the enemy. The Records of the Grand Historian say that "The flying stones weigh 12 catties and by devices [ji] are shot off 300 paces." Traction trebuchets went into decline during the Han dynasty due to long periods of peace but became a common siege weapon again during the Three Kingdoms period. They were commonly called stone-throwing machines, thunder carriages, and stone carriages in the following centuries. They were used as ship mounted weapons by 573 for attacking enemy fortifications. It seems that during the early 7th century, improvements were made on traction trebuchets, although it is not explicitly stated what. According to a stele in Barkul celebrating Tang Taizong's conquest of what is now Ejin Banner, the engineer Jiang Xingben made great advancements on trebuchets that were unknown in ancient times. Jiang Xingben participated in the construction of siege engines for Taizong's campaigns against the Western Regions. In 617 Li Mi (Sui dynasty) constructed 300 trebuchets for his assault on Luoyang, in 621 Li Shimin did the same at Luoyang, and onward into the Song dynasty when in 1161, trebuchets operated by Song dynasty soldiers fired bombs of lime and sulphur against the ships of the Jin dynasty navy during the Battle of Caishi.

"For the trebuchet they use large baulks of wood to make the framework, fixing it on four wheels below. From this there rise up two posts having between them a horizontal bar which carries a single arm so that the top of the machine is like a swape. The arm is arranged as to height, length and size, according to the city [which it is proposed to attack or defend]. At the end of the arm there is a sling which holds the stone or stones, of weight and number depending on the stoutness of the arm. Men [suddenly] pull [ropes attached to the other] end, and so shoot it forth. The carriage framework can be pushed and turned around at will. Alternatively the ends [of the beams of the framework] can be buried in the ground and so used. [But whether you use] the 'Whirlwind' type or the 'Four-footed' type depends upon the circumstances."

The traction trebuchet was adopted by various peoples west of China such as the Byzantines, Persians, Arabs, and Avars by the sixth to seventh centuries AD. Some scholars suggest that the Avars carried the traction trebuchet westward while others claim that the Byzantines already possessed knowledge of the traction trebuchet beforehand. Regardless of the vector of transmission, it appeared in the eastern Mediterranean by the late 6th century AD, where it replaced torsion powered siege engines such as the ballista and onager. The rapid displacement of torsion siege engines was probably due to a combination of reasons. The traction trebuchet is simpler in design, has a faster rate of fire, increased accuracy, and comparable range and power. It was probably also safer than the twisted cords of torsion weapons, "whose bundles of taut sinews stored up huge amounts of energy even in resting state and were prone to catastrophic failure when in use." At the same time, the late Roman Empire seems to have fielded "considerably less artillery than its forebears, organised now in separate units, so the weaponry that came into the hands of successor states might have been limited in quantity." Evidence from Gaul and Germania suggests there was substantial loss of skills and techniques in artillery further west.

According to the Miracles of Saint Demetrius, probably written around 620 by John, Archbishop of Thessaloniki, the Avaro-Slavs attacked Thessaloniki in 586 with traction trebuchets. The bombardment lasted for hours, but the operators were inaccurate and most of the shots missed their target. When one stone did reach their target, it "demolished the top of the rampart down to the walkway." The Byzantines adopted the traction trebuchet possibly as early as 587, the Persians in the early 7th century, and the Arabs in the second half of the 7th century. In 652, the Arabs used trebuchets at the siege of Dongola in the Sudan. Like the Chinese, by 653, the Arabs also had ship mounted traction trebuchets. The Franks and Saxons adopted the weapon in the 8th century. The Life of Louis the Pious contains the earliest western European reference to mangonels (traction trebuchets) in its account of the siege of Tortosa (808–809). In 1173, the Republic of Pisa tried to capture an island castle with traction trebuchet on galleys. Traction trebuchets were also used in India.

"The catapult, the account of which has been translated from the Greek several times, was quadrangular, with a wide base but narrowing towards the top, using large iron rollers to which were fixed timber beams 'similar to the beams of big houses', having at the back a sling, and at the front thick cables, enabling the arm to be raised and lowered, and which threw 'enormous blocks into the air with a terrifying noise'."

The traction trebuchet was most efficient as an anti-personnel weapon, used in a supportive position alongside archers and slingers. Most accounts of traction trebuchets describe them as light artillery weapons while actual penetration of defenses was the result of mining or siege towers. At the Siege of Kamacha in 766, Byzantine defenders used wooden cover to protect themselves from the enemy artillery while inflicting casualties with their own stone throwers. Michael the Syrian noted that at the siege of Balis in 823 it was the defenders that suffered from bombardment rather than the fortifications. At the siege of Kaysum, Abdallah ibn Tahir al-Khurasani used artillery to damage houses in the town. The Sack of Amorium in 838 saw the use of traction trebuchets to drive away defenders and destroy wooden defenses. At the siege of Marand in 848, traction trebuchets were used, "reportedly killing 100 and wounding 400 on each side during the eight-month siege." During the siege of Baghdad in 865, defensive artillery were responsible for repelling an attack on the city gate while traction trebuchets on boats claimed a hundred of the defenders' lives.

Some exceptionally large and powerful traction trebuchets have been described during the 11th century or later. At the Siege of Manzikert (1054), the Seljuks' initial siege artillery was countered by the defenders' own, which shot stones at the besieging machine. In response, the Seljuks constructed another one requiring 400 men to pull and threw stones weighing 20 kg. A breach was created on the first shot but the machine was burnt down by the defenders. According to Matthew of Edessa, this machine weighed 3,400 kg and caused a number of casualties to the city's defenders. Ibn al-Adim describes a traction trebuchet capable of throwing a man in 1089. At the siege of Haizhou in 1161, a traction trebuchet was reported to have had a range of 200 paces (over 400 m).

West of China, the traction trebuchet remained the primary siege engine until the 12th century when it was replaced by the counterweight trebuchet. In China the traction trebuchet was the primary siege engine until the counterweight trebuchet was introduced during the Mongol conquest of the Song dynasty in the 13th century.

Origins

There is little to no consensus as to where and when the counterweight trebuchet, which has been described as the "most powerful weapon of the Middle Ages", was first developed. The earliest known description and illustration of a counterweight trebuchet comes from a commentary on the conquests of Saladin by Mardi ibn Ali al-Tarsusi in 1187. However cases for the existence of both European and Muslim counterweight trebuchets prior to 1187 have been made. In 1090, Khalaf ibn Mula'ib threw out a man from the citadel in Salamiya with a machine and in the early 12th century, Muslim siege engines were able to breach crusader fortifications. David Nicolle argues that these events could have only been possible with the use of counterweight trebuchets.

Although al-Tarsusi provided the first description and illustration of a counterweight trebuchet, the text implies that the engine was not new and had previously been built. Al-Tarsusi referred to the counterweight trebuchet as the "Persian" trebuchet whereas the "Frankish" trebuchet was a light traction engine. Later during the 13th century, Muslims used manjaniq maghribi (Western trebuchet) and manjaniq ifranji (Frankish trebuchet) to refer to counterweight trebuchets. Paul E. Chevedden suggests that manjaniq maghribi was used to describe hinged counterweight engines in contrast to previous fixed or hanging counterweight trebuchets. Sometimes counterweight trebuchets are separated into two or three different categories based on how their counterweights are attached. These being fixed, hanging, and hinged counterweights. A fixed counterweight is an intrinsic part of the swinging arm and its trajectory is circular. Hanging counterweights hang below the arm and drop vertically. Hinged counterweights are attached to the arm by a swinging joint. Some fixed counterweights also had a hinged component. The type described by al-Tarsusi was a hanging counterweight. Writing in 1280, Giles of Rome claimed that hinged counterweight trebuchets had a greater range than fixed counterweight types.

Chevedden argues that counterweight trebuchets appeared prior to 1187 in Europe based on what might have been counterweight trebuchets in earlier sources. The 12th-century Byzantine historian Niketas Choniates may have been referring to a counterweight trebuchet when he described one equipped with a windlass, which is only useful to counterweight machines, at the siege of Zevgminon in 1165. However the source for this was written in the 1180s to 1190s and Niketas may have been placing the engine of his own time anachronistically into the past. At the siege of Nicaea in 1097 the Byzantine emperor Alexios I Komnenos reportedly invented new pieces of heavy artillery which deviated from the conventional design and made a deep impression on everyone. Illustrations produced later in 1270 depicted fixed counterweight trebuchets used at the siege. Possible references to counterweight trebuchets also appear for the second siege of Tyre in 1124, where the crusaders reportedly made use of "great trebuchets". However the sources for this siege, Fulcher of Chartres and William of Tyre, only mention machinae and machinae iaculatoriae that were later translated as perrieres and mangoniaux in the Estoire d'Eracles. Chevedden argues that given the references to new and better trebuchets that by the 1120–30s, the counterweight trebuchet was being used in a variety of places by different peoples such as the crusader states, the Normans of Sicily and the Seljuks.

The earliest solid reference to a "trebuchet" in European sources dates to the siege of Castelnuovo Bocca d'Adda in 1199. However it is unclear if this referred to counterweight trebuchets since the author did not specify what engine was used and described the machine as fairly light. They may have been used in Germany from around 1205. Only in the late 1210s do references to "trebuchet", describing more powerful engines and different components, more closely align with the features of a counterweight trebuchet. Some of these more powerful engines may have just been traction trebuchets, as one was described being pulled by ten thousand. At the Siege of Toulouse (1217–1218), trabuquets were mentioned to have been deployed, but the siege engine depicted at the tomb of Simon de Montfort, who was killed by artillery at the siege, is a traction trebuchet. Though soon after, clear evidence of counterweight machines appeared. According to the Song of the Albigensian Crusade, the defenders "ran to the ropes and wound the trebuchets", and to shoot the machine, they "then released their ropes." They were used in England at least by 1217 and in Iberia shortly after 1218. By the 1230s the counterweight trebuchet was a common item in siege warfare. Despite the lack of clearly definable terms in the late 12th and early 13th centuries, it is likely that both Muslims and Europeans already had working knowledge of the counterweight trebuchet beforehand. From the First Crusade (1096–1099) onward, there does not appear to be any discernible difference in the technology of siege engines employed by Muslim and Frankish forces, and by the Third Crusade (1189–1192), both sides seemed well acquainted with the enemy's siege weapons, which "appear to have been remarkably similar."

China
Counterweight trebuchets do not appear with certainty in Chinese historical records until about 1268. Prior to 1268, the counterweight trebuchet may have been used in 1232 by the Jurchen Jin commander Qiang Shen. Qiang invented a device called the "Arresting Trebuchet" which only needed a few men to work it, and could hurl great stones more than a hundred paces, further than even the strongest traction trebuchet. However no other details on the machine are given. Qiang died the following year and no further references to the Arresting Trebuchet appear. The earliest definite mention of the counterweight trebuchet in China was in 1268, when the Mongols laid siege to Fancheng and Xiangyang. After failing to take the twin cities of Fancheng and Xiangyang for several years, collectively known as the siege of Fancheng and Xiangyang, the Mongol army brought in two Persian engineers to build hinged counterweight trebuchets. Known as the Huihui trebuchet (回回砲, where "huihui" is a loose slang referring to any Muslims), or Xiangyang trebuchet (襄陽砲) because they were first encountered in that battle. Ismail and Al-aud-Din travelled to South China from Iraq and built trebuchets for the siege. Chinese and Muslim engineers operated artillery and siege engines for the Mongol armies. By 1283, counterweight trebuchets were also used in Southeast Asia by the Chams against the Yuan dynasty.

"The design of the Muslim trebuchets came originally from the Muslim countries, and they were more powerful than ordinary trebuchets. In the case of the largest ones, the wooden framework stood above a hole in the ground. The projectiles were several feet in diameter, and when they fell to the earth they made a hole three or four feet deep. when [the artillerists] wanted to hurl them to a great range, they added weight [to the counterpoise] and set it further back [on the arm] when they needed only a shorter distance, they set it forward, nearer [the fulcrum]."

Function
While some historians have described the counterweight trebuchet as a type of medieval super weapon, other historians have urged caution in overemphasizing its destructive capability. On the side of the counterweight engine as a medieval military revolution, historians such as Sydney Toy, Paul Chevedden, and Hugh Kennedy consider its power to have caused significant changes in medieval warfare. This line of thought suggests that rams were abandoned due to the effectiveness of the counterweight trebuchet, which was capable of reducing "any fortress to rubble". Accordingly, traditional fortifications became obsolete and had to be improved with new architectural structures to support defensive counterweight trebuchets. In southern France during the Albigensian Crusade, sieges were a last resort and negotiations for surrender were common. In these instances, trebuchets were used to threaten or bombard enemy fortifications and ensure victory. On the side of caution, historians such as John France, Christopher Marshall, and Michael Fulton emphasize the still considerable difficulty of reducing fortifications with siege artillery. Examples of the failure of siege artillery include the lack of evidence that artillery ever threatened the defenses of Kerak Castle between 1170 and 1188. Marshall maintains that "the methods of attack and defence remained largely the same through the thirteenth century as they had been during the twelfth." Reservations on the counterweight trebuchet's destructive capability were expressed by Viollet-le-Duc, who "asserted that even counterweight-powered artillery could do little more than destroy crenellations, clear defenders from parapets and target the machines of the besieged."

In spite of the evidence regarding increasingly powerful counterweight trebuchets during the 13th century, "it remains an important consideration that not one of these appears to have effected a breach that directly led to the fall of a stronghold." In 1220, Al-Mu'azzam Isa laid siege to Atlit with a trabuculus, three petrariae, and four mangonelli but could not penetrate past the outer wall, which was soft but thick. As late as the Siege of Acre (1291), where the Mamluk Sultanate fielded 72 or 92 trebuchets, including 14 or 15 counterweight trebuchets and the remaining traction types, they were never able to fulfill a breaching role. The Mamluks entered the city by sapping the northeast corner of the outer wall. Though stone projectiles of substantial size (~66 kg) have been found at Acre, located near the site of the siege and likely used by the Mamluks, surviving walls of a 13th-century Montmusard tower are no more than one meter thick. There is no indication that the thickness of fortress walls increased exponentially rather than a modest increase of 0.5–1 m between the 12th and 13th century. The Templar of Tyre described the faster firing traction trebuchets as more dangerous to the defenders than the counterweight ones. The Song dynasty described countermeasures against counterweight trebuchets that prevented them from damaging towers and houses: "an extraordinary method was invented of neutralising the effects of the enemy's trebuchets. Ropes of rice straw four inches thick and thirty-four feet long were joined together twenty at a time, draped on to the buildings from top to bottom, and covered with [wet] clay. Then neither the incendiary arrows, nor bombs [huo pao] from trebuchets, nor even stones of a hundred jun caused any damage to the towers and houses."

The counterweight trebuchet did not completely replace the traction trebuchet. Despite its greater range, counterweight trebuchets had to be constructed close to the site of the siege unlike traction trebuchets, which were smaller, lighter, cheaper, and easier to take apart and put back together again where necessary. The superiority of the counterweight trebuchet was not clear cut. Of this, the Hongwu Emperor stated in 1388: "The old type of trebuchet was really more convenient. If you have a hundred of those machines, then when you are ready to march, each wooden pole can be carried by only four men. Then when you reach your destination, you encircle the city, set them up, and start shooting!" The traction trebuchet continued to serve as an anti-personnel weapon. The Norwegian text of 1240, Speculum regale, explicitly states this division of functions. Traction trebuchets were to be used for hitting people in undefended areas. At the Siege of Acre (1291), both traction and counterweight trebuchets were used. The traction trebuchets provided cover fire while the counterweight trebuchets destroyed the city's fortifications. The counterweight-trebuchet could also be used for cover fire and as an anti-personnel weapon. King James I of Aragon employed this as a defensive tactic in many fortified structures and towns which proved effective. Trebuchets could cause mass casualties due to the destruction of structures. During an assault on Muntcada by King James I, a trebuchet was used to target a tower, destroying the structure and causing the consequential deaths of civilians and livestock. But typically the counterweight trebuchet was used against battlements such as parapets, other defensive structures, and the lower section of walls due to its greater accuracy and longer range, which was how it was employed by the Kingdom of Aragon.

"Rather than replace traction trebuchets, counterweight trebuchets supplemented them in a different role. Their slower shooting rate and greater mass made them more difficult to reposition, or even yaw, leaving few incentives to employ a small counterweight engine rather than a comparable traction type. Although less accurate, traction trebuchets might be expected to achieve the same result, albeit with more shots, in a similar amount of time. Accordingly, it was only profitable to employ counterweight trebuchets if they were capable of harnessing noticeably more energy, allowing them to throw significantly larger stones or similarly sized stones greater distances."

There is some evidence that the counterweight trebuchet could be transported. Armies employed a magister tormentorum ('master of trebuchets') for the reconstruction of trebuchets after they were deconstructed for transportation to their destination, whether on carts or by ship. They could also be equipped with their own wheels, as shown in two 17th- and 18th-century Chinese illustrations, which are also the only Chinese depictions of counterweight trebuchets on land. According to Liang Jieming, the "illustration shows... its throwing arm disassembled, its counterweight locked with supporting braces, and prepped for transport and not in battle deployment." However, according to Joseph Needham, the large tank in the middle was the counterweight, while the bulb at the end of the arm was for adjusting between fixed and swinging counterweights. Both Liang and Needham note that the illustrations are poorly drawn and confusing, leading to mislabeling.

The counterweight and traction trebuchets were phased out around the mid-15th century in favor of gunpowder weapons.

Decline of military use
With the introduction of gunpowder, the trebuchet began to lose its place as the siege engine of choice to the cannon. Trebuchets were still used both at the siege of Burgos (1475–1476) and siege of Rhodes (1480). One of the last recorded military uses was by Hernán Cortés, at the 1521 siege of the Aztec capital Tenochtitlán. Accounts of the attack note that its use was motivated by the limited supply of gunpowder. The attempt was reportedly unsuccessful: the first projectile landed on the trebuchet itself, destroying it.

In China, the last time trebuchets were seriously considered for military purposes was in 1480. Not much is heard of them afterwards.

In 2024, the Israeli military made at least partial use of trebuchets against Hezbollah objectives in southern Lebanon.

Hand-trebuchet
The hand-trebuchet (χειρομάγγανον, cheiromanganon) was a staff sling mounted on a pole using a lever mechanism to propel projectiles. Basically a one-man traction trebuchet, it was used by troops of emperor Nikephoros II Phokas around 965 to disrupt enemy formations in the open field. It was also mentioned in the Taktika of general Nikephoros Ouranos (c. 1000), and listed in De obsidione toleranda (author anonymous) as a form of artillery.

In China, the hand-trebuchet (shoupao) was invented by Liu Yongxi and presented to the emperor in 1002. It was a pole with a pin at its upper end that acted as a fulcrum for the arm. The pole was used as a shot for fixing in the ground and the user could then throw missiles at the enemy from a static position.

Hybrid trebuchet
According to Paul E. Chevedden, a hybrid trebuchet existed that used both counterweight and human propulsion. However no illustrations or descriptions of the device exist from the time when they were supposed to have been used. The entire argument for the existence of hybrid trebuchets rests on accounts of increasingly more effective siege weapons. Peter Purton suggests that this was simply because the machines became larger. The earliest depiction of a hybrid trebuchet is dated to 1462, when trebuchets had already become obsolete due to cannons.

Couillard
The couillard is a smaller version of a counterweight trebuchet with a single frame instead of the usual double "A" frames. The counterweight is split into two halves to avoid hitting the center frame.

Recreation and education
Most trebuchet use in recent centuries has been for recreational or educational, rather than military purposes. New machines have been constructed and old ones restored by living history enthusiasts, for historical re-enactments, and use in other historical celebrations. As their construction is substantially simpler than modern weapons, trebuchets also serve as the object of engineering challenges.

The methods of trebuchet construction were lost at the beginning of the 16th century. In 1984, the French engineer Renaud Beffeyte made the first modern reconstruction of a trebuchet, based on documents from 1324.

The largest currently-functioning trebuchet in the world is the 22,000 kg machine at Warwick Castle, England, constructed in 2005. Based on historical designs, it stands 18 m tall and throws missiles typically 36 kg (80 lbs) up to 300 m. The trebuchet gained significant interest from numerous news sources when in 2015 a burning missile fired from the siege engine struck and damaged a Victorian-era boathouse situated at the River Avon close by, inadvertently demonstrating the weapon's power. It is built on the design of a similar trebuchet at Middelaldercentret in Denmark. In 1989, Middelaldercentret became the first place in the modern era to have a working trebuchet.

Trebuchets compete in one of the classifications of machines used to hurl pumpkins at the annual pumpkin chucking contest held in Sussex County, Delaware, U.S. The record-holder in that contest for trebuchets is the Yankee Siege II from New Hampshire, which at the 2013 WCPC Championship tossed a pumpkin 2835.8 ft (864.35 metres). The 51 ft, 55000 lb trebuchet flings the standard 8 - 10 lb pumpkins, specified for all entries in the WCPC competition.

A large trebuchet was tested in late 2017 in Belfast as part of the set for the television series Game of Thrones.

A large trebuchet based on Edward I's "Warwolf" was constructed for a scene in David Mackenzie's movie Outlaw King (2018) about Robert the Bruce, King of Scots. During the film, it hurls an incendiary projectile at Stirling Castle. It recreates the true story that it took some three months to build and Edward would not let his enemy surrender until he could use it.

In recent years several trebuchets has been created capable of throwing cars. In the episode "Carnage A Trois" in series 4 of The Grand Tour the presenters uses a trebuchet to allegedly sling a Citroën C3 Pluriel from the White Cliffs of Dover across the English Channel. The Stamford based YouTube personality and inventor Colin Furze created a 14 m high trebuchet capable of throwing a washing machine in December 2020.

Developments
Although rarely used as a weapon today, trebuchets maintain the interest of professional and hobbyist engineers. One modern technological development, especially for the competitive pumpkin-hurling events, is the "floating arms" design. Instead of using the traditional axle fixed to a frame, these devices are mounted on wheels that roll on a track parallel to the ground, with a counterweight that falls directly downward upon release, allowing for greater efficiency by increasing the proportion of energy transferred to the projectile. A more radical design; Jonathan, Orion, and Emmerson Stapleton's "walking arm", described as "...a stick falling over with a huge counterweight on top of the stick..." debuted in 2016 and in 2018 won both the Grand Champion Best Design and Middleweight Open Division of the 10th annual Vermont Pumpkin Chuckin Festival. Another recent development is the "flywheel trebuchet," in which a flywheel is spun into rapid rotation to build up momentum before release.

Uses in activism and insurgency
In 2013, during the Syrian civil war, rebels were filmed using a trebuchet in the Battle of Aleppo. The trebuchet was used to project explosives at government troops.

In 2014, during the Hrushevskoho street riots in Ukraine, rioters used an improvised trebuchet to throw bricks and Molotov cocktails at the Berkut.

Uses in regular armies
In 2024, the IDF used a trebuchet to hurl flaming projectiles into Lebanon. The goal was to burn down the thicket that grew alongside the border wall between Israel and Lebanon, so it couldn't be used as cover by Hezbollah troops. The IDF later issued a response to suggest that the trebuchet's use was a "local initiative", rather than a widely-used tool in the Israeli military.

title: Trebuchet