Catapults were long-range weapons designed to help destroy castles in the Middle Ages. They typically consisted of a throwing arm armed with a basket to hold the desired projectile, which would then launch the projectile.
Catapults could be built on top of a wheeled structure to provide mobility for the device if needed. They could be used for both defending and attacking, and were sometimes mounted on castle walls to defend against an enemy siege. Attackers would use catapults to weaken and destroy walls that could not be assaulted with typical weaponry. They would also use the catapults to set susceptible areas on fire with flammable projectiles.
Several types of catapults existed, such as mangonels, ballistae and trebuchets. Mangonels were catapults that utilized force of torsion caused by twisting ropes and releasing them, allowing the mangonel to launch its projectile. Ballistae used torsion as well, and its design resembled that of an oversized crossbow, firing large bolts to damage castle walls or killing multiple enemy troops. The ballista originated from a weapon designed by the Greeks called a gastraphete, which was basically a smaller version of a ballista. Trebuchets were very large catapults that used a system of weights to launch large projectiles over very long distances.