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Trebuchet, a Medieval Siege Engine

M edieval warfare consisted of other things too besides knights dashing about and peasants getting killed in general. One important feature was holding cities besieged. Some of the sieges lasted pretty damn long, until the besieged city capitulated or the besiegers got bored or were chased away. Sieges featured siege engines on both sides, as an attack and a defensive weapon.

F irst on the scene were catapults. These were in effect large bows whose energy was derived from twisted ropes or sinews. As a consequence, their effectiveness was modest at best, as many castles such as Acre sported walls up to 6 metres thick. The biggest catapults were able to hurl projectiles of 16 - 27 kilograms to distances of some 180 metres. Stone projectiles did little harm to the fortresses, but they did succeed well enough against unshielded humans.

E nter the trebuchet. This contraption was fully able to hurl projectiles weighing a thousand kilograms. That kind of shots surely caused great havoc even in the sturdiest of structures. The trebuchet is effectively a gigantic sling that uses the potential energy of a raised counterweight to power its projectiles. A pivoted arm has the counterweight at one end and the payload (if you could call it that) at the other, connected to a rope hammock. When the trebuchet was fired, the weight fell and the arm hurled the payload on a trajectory which most often ended on some poor person's neck.

A crude trebuchet

T rebuchets reached the Mediterranean from China in the late sixth century and became one of the favourite weapons of the Arabs in their conquests. They were built both as stationary and mobile. In the early models, the counterweight was not yet invented, or it was supplemented by the joint pulling effort of up to a couple hundred people. Invention of the said weight increased the range of the weapon consideraby, and version 3.0 included a hinged counterweight that attained formidable power. In the top-of-the-line models the counterweight was the size of a peasant's hut, and weighed tens of tons. Such weapons are on record as having thrown projectiles weighing 900 to 1360 kilograms. Not just stones were used, dead horses were also considered useful ammo, as were bundled human corpses. It was just the corpses of Mongols, dead of the Black Death, that helped launch the famed epidemic in 1346 when the Mongols laid siege to Kaffa in Constantinople.

A more cheerful side note: trebuchets contributed to the development of the word 'engineer'. In Latin vernacular, the trebuchet was called ingenium, for ingenious contrivance, and those who built them were called ingeniators, from whence 'engineer' is just one step away. Detailed data on the trebuchet can be found in the July 1995 issue of Scientific American, pages 58 to 63. The story includes a hilarious sequence of pictures in which a modern reconstruction of a trebuchet hurls a piano to a considerable distance at which it fails to survive touchdown.

Armory Bailey Barracks Chapel Dungeon Library Pub

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