Trebuchet
A trebuchet is a type of catapult that uses a hinged 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 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 via 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, the traction trebuchet was called the pao while the counterweight trebuchet was called the húihúi pào.The English word trebuchet is first mentioned in the 14th century as "medieval stone-throwing engine of war". It is borrowed from French trebuchet.
The French word is from the verbal root of trebucher : trebuch- + diminutive noun suffix -et, trebucher meant "to overthrow, to bring down", then and now "to stumble", maybe earlier "to rock" or "to tilt". It is a compound of French tre-, variant form 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 1174–1177 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" while the 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. 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, 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, 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. 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 attached to the shorter end of the beam, 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. 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 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.
History
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. According to the Mozi, the traction trebuchet was high with buried below ground, the fulcrum attached was constructed from the wheels of a cart, the throwing arm was long with three quarters above the pivot and a quarter below to which the ropes are attached, and the sling long. The range given for projectiles are,, and. 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 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 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 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.
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 in its account of the siege of Tortosa. 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 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, 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. 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 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.
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.