Trebuchet: Difference between revisions

Trebuchets at Château de Castelnaud

Counterweight trebuchet constructed on the design of the "Warwolf"

File:Trebuchet simulator strobe picture.jpg

A strobe picture of a simulated trebuchet in action

Sketch of an Onager, a torsion siege engine, from Antique technology by Diels.

Medieval traction trebuchet next to a staff slinger

For the typeface, see Trebuchet MS. For the chess term for the side to move loses, see Zugzwang.

A trebuchet or trebucket (from the French: trébuchet) is a siege engine that was employed in the Middle Ages either to smash masonry walls or to lob projectiles over them and into the castle under siege. It is sometimes called a "counterweight trebuchet" or "counterpoise trebuchet" in order to distinguish it from an earlier weapon that has come to be called the "traction trebuchet", the original version with pulling men instead of a counterweight. Manpowered trebuchets appeared in the Greek world and China in about the 4th century BC.

The counterweight trebuchet appeared in both Christian and Muslim lands around the Mediterranean in the twelfth century. It could fling projectiles of up to three hundred and fifty pounds (140 kg) at high speeds into enemy fortifications. Occasionally, disease-infected corpses were flung into cities in an attempt to infect or terrorize the people under siege—a medieval form of biological warfare.

The trebuchet did not become obsolete until the 16th century, well after the introduction of gunpowder. Trebuchets were far more accurate than other medieval catapults.

The basic workings of a trebuchet

A trebuchet is a type of catapult that works by using the energy of a raised counterweight to throw the projectile. Initially, the sling, which has a pouch containing the projectile, is placed in a trough below the axle, which supports the beam. Upon releasing the trigger, the sling and the beam swing around toward the vertical position, where one end of the sling releases, opening the pouch and propelling the projectile towards the target. The efficiency of the transfer of the stored energy of the counterweight to the projectile can be quite high, even without, for example, restraining the path of the counterweight. Modern day enthusiasts have varied the original design, especially to control the path of the counterweight. There is debate about whether wheels improve the efficiency of transfer of energy from the counterweight to the projectile.

Trebuchets versus torsion

The trebuchet is often confused with the earlier torsion siege engines. The main difference is that a torsion siege engine (examples of which include the onager and ballista) uses a twisted rope or twine to provide power, whereas a trebuchet uses a counterweight, usually much closer to the fulcrum than the payload for mechanical advantage, though this is not necessary. A trebuchet also has a sling holding the projectile, and a means for releasing it at the right moment for maximum range. Both trebuchets and torsion siege engines are classified under the generic term "catapult," which includes any non-handheld mechanical device designed to hurl an object.

History

Traction trebuchet

The trebuchet derives from the ancient sling. A variation of the sling, called staff sling (Latin: fustibalus), contained a short piece of wood to extend the arm and provide greater leverage. This evolved into the traction trebuchet in which a number of people pull on ropes attached to the short arm of a lever that has a sling on the long arm. This type of trebuchet is smaller and has a shorter range, but is a more portable machine and has a faster rate of fire than larger, counterweight-powered types. The smallest traction trebuchets could be powered by the weight and pulling strength of one person using a single rope, but most were designed and sized for between 15 and 45 men, generally two per rope. These teams would sometimes be local citizens helping in the siege or in the defense of their town. Traction trebuchets had a range of 100 to 200 feet when casting weights up to 250 pounds. It is believed that the first traction trebuchets were used by the Mohists in China as early as in the 5th century BC, descriptions of which can be found in the Mojing (compiled in the 4th century BC). The Chinese named the later counterweight trebuchet Huihui Pao (Muslim Weapons, "huihui" means Muslim) or Xiangyang Pao (襄陽砲), where Pao means bombard.

The traction trebuchet next appeared in Byzantium. The Strategikon of Emperor Maurice, composed in the late 6th century, calls for "ballistae revolving in both directions," (Βαλλίστρας έκατηρωθεν στρεφόμενας), probably traction trebuchets (Dennis 1998, p. 99). The Miracles of St. Demetrius, composed by John I, archbishop of Thessalonike, clearly describe traction trebuchets in the Avaro-Slav artillery: "Hanging from the back sides of these pieces of timber were slings and from the front strong ropes, by which, pulling down and releasing the sling, they propel the stones up high and with a loud noise." (John I 597 1:154, ed. Lemerle 1979)

They were also used with great effect by the Islamic armies during the Muslim conquests. A surviving Arab technical treatise on these machines is Kitab Aniq fi al-Manajaniq ( كتاب أنيق في المنجنيق, An Elegant Book on Trebuchets), written in 1462 by Yusuf ibn Urunbugha al-Zaradkash. It provides detailed construction and operating information.

There is some doubt as to the exact period in which traction trebuchets, or knowledge of them, reached Scandinavia. The Vikings may have known of them at a very early stage, as the monk Abbo de St. Germain reports on the siege of Paris in his epic De bello Parisiaco dated about 890 that engines of war were used. Another source mentions that Nordic people or "the Norsemen" used engines of war at the siege of Angers as early as 873.

Hand-trebuchet

The hand-trebuchet (Greek: cheiromangana) was a staff sling mounted on a pole using a lever mechanism to propel projectiles. Basically a portable trebuchet which could be operated by a single man, it was used by 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 (ca. 1000), and listed in the Anonymus De obsidione toleranda as a form of artillery.

Counterweight trebuchet

Counterweight trebuchet at Château des Baux, France

Counterweight trebuchet by the German engineer Konrad Kyeser (ca. 1405)

19th century French three-quarter drawing of a medieval counterweight trebuchet

Side view of counterweight trebuchet

The earliest written record of the counterweight trebuchet, much more powerful than the traction version, appears in the work of the 12th century Byzantine historian Niketas Choniates. Niketas describes a trebuchet used by Andronikos I Komnenos, future Byzantine emperor, at the siege of Zevgminon in 1165 which was equipped with a windlass, an apparatus which was required neither for traction nor hybrid trebuchets to launch missiles. Chevedden dates the invention of the new artillery type back to the Siege of Nicaea in 1097 when the Byzantine emperor Alexios I Komnenos, an ally of the besieging crusaders, was reported to have invented new pieces of heavy artillery which deviated from the conventional design and made a deep impression on everyone.

The dramatic increase in military performance is for the first time reflected in historical records on the occasion of the second siege of Tyre in 1124, when the crusaders reportedly made use of "great trebuchets". By the 1120–30s, the counterweight trebuchet had diffused not only to the crusaders states, but probably also westwards to the Normans of Sicily and eastwards to the Great Seljuqs. The military use of the new gravity-powered artillery culminated in the 12th century during the Siege of Acre (1189–91) which saw the kings Richard I of England and Philip II of France wrestle for control of the city with Saladin's forces.

The only pictorial evidence of a counterweight trebuchet in the 12th century comes from an Islamic scholar, Mardi bin Ali al-Tarsusi, who wrote a military manual for Saladin circa 1187 based on information collected from an Armenian weapon expert in Muslim service. He describes a hybrid trebuchet that he said had the same hurling power as a traction machine pulled by fifty men due to "the constant force [of gravity], whereas men differ in their pulling force." (Showing his mechanical proficiency, Tarsusi designed his trebuchet so that as it was fired it cocked a supplementary crossbow, probably to protect the engineers from attack.) He allegedly wrote "Trebuchets are machines invented by unbelieving devils." (Al-Tarsusi, Bodleian MS 264). This suggests that by the time of Saladin, Muslims were acquainted with counterweight engines, but did not believe that they had invented these machines.

During the Crusades, Philip II of France named two of the trebuchets he used in the Siege of Acre in 1191 "God's Stone-Thrower" and "Bad Neighbor." During a siege of Stirling Castle in 1304, Edward Longshanks ordered his engineers to make a giant trebuchet for the English army, named "Warwolf". Range and size of the weapons varied. In 1421 the future Charles VII of France commissioned a trebuchet (coyllar) that could shoot a stone of 800 kg, while in 1188 at Ashyun, rocks up to 1,500 kg were used. Average weight of the projectiles was probably around 50–100 kg, with a range of ca. 300 metres. Rate of fire could be noteworthy: at the siege of Lisbon (1147), two engines were capable of launching a stone every 15 seconds. Also human corpses could be used in special occasion: in 1422 Prince Korybut, for example, in the siege of Karlštejn Castle shot men and manure within the enemy walls, apparently managing to spread infection among the defenders. The largest trebuchets needed exceptional quantities of timber: at the Siege of Damietta, in 1249, Louis IX of France was able to build a stockade for the whole Crusade camp with the wood from 24 captured Egyptian trebuchets.

Counterweight trebuchets do not appear with certainty in Chinese historical records until about 1268, when the Mongols laid siege to Fancheng and Xiangyang. At the Siege of Fancheng and Xiangyang, the Mongol army, unable to capture the cities despite besieging the Song defenders for years, brought in two Persian engineers who built hinged counterweight trebuchets and soon reduced the cities to rubble, forcing the surrender of the garrison. These engines were called by the Chinese historians the Huihui Pao (回回砲)("huihui" means Muslim) or Xiangyang Pao (襄陽砲), because they were first encountered in that battle. Recent research by Paul E. Chevedden indicates that the hui-hui pao was actually a European design, a double-counterweight engine that had been introduced to the Levant by Holy Roman Emperor Frederick II (1210–1250) only shortly before. The Muslim historian Rashid-al-Din Hamadani (1247?–1318) refers in his universal history to the Mongol trebuchets used at the Song cities as "Frankish" or "European trebuchets" ("manjaniq ifranji" or "manjaniq firanji"):

Before that there had not been any large Frankish catapult in Cathay [i.e. China], but Talib, a catapult-maker from this land, had gone to Baalbek and Damascus, and his sons Abubakr, Ibrahim, and Muhammad, and his employees made seven large catapults and set out to conquer the city [Sayan Fu or Hsiang-yang fu = modern Xiangfan].

With the introduction of gunpowder, the trebuchet lost its place as the siege engine of choice to the cannon. Trebuchets were 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 1779, British forces defending Gibraltar, finding that their cannons were unable to fire far enough for some purposes, constructed a trebuchet. It is unknown how successful this was: the Spanish attackers were eventually defeated, but this was largely due to a sortie.

Modern recreational use

Trebuchets are popular in modern times in a number of contexts. In particular, traditional models are constructed by historical re-enactment and living history enthusiasts, and others use the trebuchet as an engineering challenge.

Trebuchets are used to throw pumpkins at the annual pumpkin chunking contest held in Sussex County, Delaware. The record-holder in that contest for trebuchets is the Yankee Siege, which at the 2009 Championship tossed a pumpkin 2034 feet. The 51 foot tall, 55,000 pound trebuchet fires 8–10 pound pumpkins.

Modern engineering thought and materials have come up with several non-traditional designs, in particular, several with "floating arms" to increase efficiency.

Floating-arm Trebuchet

A floating-arm trebuchet is an efficient modern variant. Rather than having an axle fixed to the frame, it is mounted on wheels that roll on a track parallel to the ground, and the counterweight is constrained to fall in a direct path downwards upon the release. This increases the proportion of energy transferred to the projectile.

King Arthur Trebuchet

The King Arthur is often regarded as the most efficient trebuchet design, invented by Chris Gerow in 2001 in his efforts to compete in the Pumpkin Chunking championship. In this design, the arm is locked with the hanger when cocked. The arm points nearly straight down, and the hanger points nearly up. When the hanger is released, then when it reaches the optimum point, the secondary trigger is pulled, releasing the arm.

See also

• Catapult
• Medieval Warfare
• Onager
• Siege Engine

References

Notes

Bibliography

• Chevedden, Paul E. (1995). "The Trebuchet" (PDF). Scientific American: 66–71. {{cite journal}}: Unknown parameter |coauthors= ignored (|author= suggested) (help); Unknown parameter |month= ignored (help). Original version.
• Chevedden, Paul E. (2000). "The Invention of the Counterweight Trebuchet: A Study in Cultural Diffusion". Dumbarton Oaks Papers. 54: 71–116. doi:10.2307/1291833.
• Dennis, George (1998). "Byzantine Heavy Artillery: The Helepolis". Greek, Roman, and Byzantine Studies (39).
• Gravett, Christopher (1990). Medieval Siege Warfare. Osprey Publishing.
• Hansen, Peter Vemming (1992). "Medieval Siege Engines Reconstructed: The Witch with Ropes for Hair". Military Illustrated (47): 15–20. {{cite journal}}: Unknown parameter |month= ignored (help)
• Hansen, Peter Vemming (1992). "Experimental Reconstruction of the Medieval Trebuchet" ( – ^{Scholar search}). Acta Archelologica (63): 189–208. {{cite journal}}: External link in |format= (help)
• Jahsman, William E. (2000). The Counterweighted Trebuchet – an Excellent Example of Applied Retromechanics. {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Jahsman, William E. (2001). FATAnalysis (PDF). {{cite book}}: Unknown parameter |coauthors= ignored (|author= suggested) (help)
• Archbishop of Thessalonike, John I (1979). Miracula S. Demetrii, ed. P. Lemerle, Les plus anciens recueils des miracles de saint Demitrius et la penetration des slaves dans les Balkans. Centre National de la Recherche Scientifique.
• Liang, Jieming (2006). Chinese Siege Warfare: Mechanical Artillery & Siege Weapons of Antiquity – An Illustrated History.
• Needham, Joseph (2004). Science and Civilization in China. Cambridge University Press. p. 218.
• Needham, Joseph (1986). Science and Civilization in China: Volume 4, Part 2. Taipei: Caves Books, Ltd.
• Payne-Gallwey, Sir Ralph (1903 Reprinted). "LVIII The Trebuchet". The Crossbow With a Treatise on the Balista and Catapult of the Ancients and an Appendix on the Catapult, Balista and Turkish Bow. pp. 308–315. {{cite book}}: Check date values in: |date= (help)
• Saimre, Tanel (2007). TREBUCHET – A GRAVITY-OPERATED SIEGE ENGINE A Study in Experimental Archaeology (PDF).
• Siano, Donald B. (March 28, 2001). Trebuchet Mechanics (PDF).
• Al-Tarsusi (1947). Instruction of the masters on the means of deliverance from disasters in wars. Bodleian MS Hunt. 264. ed. Cahen, Claude, "Un traite d'armurerie compose pour Saladin". Bulletin d'etudes orientales 12 [1947–1948]:103–163.

External links

• Secrets of Lost Empires: Medieval Siege (building of and history of trebuchets), from the NOVA website
• Historical accounts of the trebuchet
• Warwick trebuchet
• Video Demonstration of the Medieval Siege Society's trebuchet
• Download Trebuchet Plans
• Caerphilly Castle trebuchet firing
• Trebuchet Animation
• Trebuchet de l'AMQ a St-Marcellin. on YouTube
• Slow motion mini trebuchet. on YouTube
• Floating Arm Trebuchet. on YouTube
• Yankee Siege Trebuchet Home Page [4]