AEMMA's interest in historical European medieval martial arts also extends to some elements of medieval warfare. A number of senior members expressed an interest in researching medieval "siege engines" or trébuchets. Having worked with the ROM on a number of occassions with collaborative presentations in the past, the ROM had in their possession a traction trébuchet which had raised our interest in this part of medieval military history. 
Our interest resulted in the donation of the traction trebuchet from the Royal Ontario Museum (ROM) to AEMMA. We were very pleased and excited over this acquisition and have focused some resource and effort to enhancing our understanding of the physics and history behind the trébuchet. With this in mind, there is no formalized "trébuchet" training program at AEMMA. The trébuchet is brought out on special occassions and events, and the launching of missles is open to all AEMMA students. The trébuchet offers the students a unique opportunity to explore the application of physics with respect to distance, speed, force, trajectory and targeting using an advanced computer program to simulate the trébuchet's behaviour in order to calculate the optimum range, weight and force required to successfully strike a target. Of course, this version of the trébuchet requires raw "muscle" power to operate the trébuchet providing both an intellectual stimulating activity as well as plain old fun!
Trébuchets come in two forms: counter-weight (see images below) and the traction trébuchet (above left and right). Traction trébuchets require human muscle to fire a projectile. The photo above right depicts the trébuchet donated by the ROM.
Brief History by Sir Ralph Payne-Gallwey 1903
This engine was of much more recent invention than either the catapult or the balista of the Greeks and Romans. It is said to have been introduced into siege operations by the French in the twelfth century. On the other hand, the catapult and the balista were in use before the Christian era. Egiclio Colonna gives a fairly- accurate description of the trebuchet and writes of it about 1280 as though it were the most effective siege weapon of his time.
The projectile force of this weapon was obtained from the terrestrial gravitation of a heavy weight, and not from twisted cordage as in the catapult and balista.
From about the middle of the thirteenth century, the trebuchet in great measure superseded the catapult. This preference for the trebuchet was due to the fact that it was able to cast stones of 300 lbs. and more in weight or five or six times as heavy as those which the largest catapults could project.
The stones of 50 to 60 lbs. thrown by siege catapults would no doubt destroy towers and battlements, as the result of the constant and concentrated bombardment of many engines. One huge stone of 300 lbs., as slung from a trebuchet, would however shake the strongest defensive masonry and easily break through the upper parts of the walls of a fortress.
The trebuchet was essentially an engine for destroying the defences of a fortification, so that it might be entered by means of scaling ladders or in other ways. From experiments with models of good size and from other sources I find that the largest trebuchets those with arms of about 50 ft. in length and counterpoises of about 20,000 lbs. - were capable of slinging a Stone 300 lbs. in weight to a distance of 300 yards, a range of 350 yards being in my opinion more than these engines were able to attain.
The trebuchet made by order of Napoleon III., and described in his ' Etudes sur l'artillerie,' had an arm 33 ft. in length with a counterpoise of 10,000 lbs. weight to work it. This machine projected a 50 lb. cannon-ball 200 yards, but was so lightly constructed that its full power could not be safely applied.
In a book on ' Experimental Philosophy,' by J.T. Desaguliers, 1734 a curious and interesting old work on mechanical effects, the author gives a detailed calculation of the power of a trebuchet, together with plans of the engine as constructed from the writings of Vitruvius.
These drawings are, however, inaccurate, and though Desaguliers' conclusions are exact, he only allows the trebuchet a counterpoise of 2,000 lbs. which would be far too light a weight to be of any service in an engine of the kind.
The trebuchet is sometimes depicted in medieval books with an arm like that of a catapult (i.e. with a hollow in the end of the arm in which to rest the stone), and without a sling, but this is incorrect.
The trebuchet always had a sling in which to place its missile. The sling- doubled the power of the engine and caused it to throw its projectile twice as far as it would have been able to do without it. It was the length of the arm, when suitably weighted with its counterpoise, which combined with its sling gave power to the trebuchet. Its arm, when released, swung round with a long easy sweep and with nothing approaching the velocity of the much shorter arm of the catapult. The weight of the projectile cast by a trebuchet was governed by the weight of its counterpoise. Provided the engine was of sufficient strength and could be manipulated, there was scarce a limit to its power.
Numerous references are to be found in medieval authors to the practice of throwing dead horses into a besieged town with a view to causing a pestilence therein, and there can be no doubt that trebuchets were employed for this purpose. As a small horse weighs about 10 cwt., we can form some idea of the size of the rocks and balls of stone that trebuchets were capable of slinging. When we consider that a trebuchet was able to throw a horse over the walls of a town we credit credit the statement of Stella who writes ‘that the Genoese armament sent against Cyprus in 1373 had among other great engines one which cast stones of 12 cwt.’ Villard de Honnecourt describes a trebuchet that had a counterpoise of sand the frame of which was 12 ft. long, 8 ft. broad, and 2 ft. deep. That such machines were of vast size will readily he understood.
There is no "formalized" regular trébuchet training at AEMMA. Training occurs when an opportunity presents itself to the Academy such as an event in which we are able to assemble and fire the trébuchet approximately once or twice a year.
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References