A catapult is a war siege machine used to throw projectiles at great distances, without the use of any explosive comparable on this point to other siege engines in use during Antiquity and the Middle Ages. Any castle siege or even battles in open fields would not go without a catapult.
The catapult, which was associated with the ballista, which projected spears, was capable of projecting heavy stones or even, according to the scruples of the warlords, corpses or various droppings in order to undermine the enemy’s morale, scare them, or even spread infections with a strained cable. The stones thrown could reach the weight of sixty kilos.
The propulsive force was first given by the bending of a giant arc and then, in the more sophisticated gears, by the twisting of a “spring” consisting of a bundle of fibers.