"The trebuchet was the dominant siege weapon... lasting 100 years after the [arrival] of gunpowder."
University of Arkansas website
The trebuchet was an ancient form of artillery that first appeared in China in the fifth century B.C.E. The weapon of mass destruction of its time, it was an improvement on the catapult. Unlike other catapults, such as the mangonel that uses twisted rope to provide power, the trebuchet uses a counterweight to provide its force. The trebuchet dominated long-range artillery until the sixteenth century,
The main arm of a trebuchet is attached to a fulcrum in such a way that the end holding the counterweight is much closer to the fulcrum than the end that holds the projectile. As the counterweight is released, the short end of the arm drops downward rapidly. Because of the longer length on the other side of the fulcrum, the end holding the projectile is flung upward in an arc at a much faster rate, giving considerable velocity to any missile thrown from it. This effect is usually increased by adding a sling to the firing end that also swings outward while firing, effectively increasing the power of the trebuchet.
Trebuchets were far more powerful and accurate than earlier catapults and, by the time they appeared in the Mediterranean region, around 1100, they had evolved into terrifying machines of war that could be easily maneuvered to lay siege to castles with strong fortifications. They were primarily used to batter down stone walls by repeatedly firing at points of weakness, Boulders weighing as much as 300 pounds (140 kg) were pounded into fortified walls.
The trebuchet also served as an early form of biological warfare in that ordure, diseased animals, and rotting corpses were launched into besieged towns and forts. Not only did these spread disease, but having former comrades raining down from the sky had a powerfully negative impact on morale.
