Catapults are weapons capable of hurling a projectile a great distance. They come in three main forms. The first are tensional catapults, which work very much like a giant crossbow, and were the earliest to be developed. The second are torsional catapults, which work by bending back and releasing an arm. The third and most advanced is the trebuchet, which works like a giant sling.
The first catapults appear in later Greek times, early adopters being Dionysius of Syracuse, Onomarchus of Phocis, and Alexander the Great, who introduced the idea of using them as cover on the battlefield as well as in sieges. They were more fully developed in Roman and Medieval times, the trebuchet being introduced a relatively short-time before the advent of gunpowder, which made the catapult more or less obsolete. Catapults were usually assembled at the site of a siege, and an army carried few or no pieces of it with them.
- See also : Medieval siege weaponry