 Replica catapult at Château des Baux, France Catapults are siege engines using an arm to hurl a projectile a great distance. Any machine that hurls an object can be considered a catapult, but the term is generally understood to mean medieval siege weapons.
Catapults were usually assembled at the site of a siege, and an army carried few or no pieces of it with them because wood was easily available on site.
Types
Catapults can be classified according to the physical concept used to store and release the energy required to propel the projectile.
The first catapults were tensional catapults, developed from the Roman ballista. A member under tension propels the throwing arm, very much like a giant crossbow. A small simple version is used as a toy.
Subsequently, torsional catapults were developed, such as the mangonel and the onager. Mangonels have an arm with a bucket or cup to hold the projectile at one end. The bottom end of the throwing arm is inserted in rope or fibers that are twisted, providing the force to propel the arm.
The most sophisticated catapult is a trebuchet, which uses gravity rather than tension or torsion to propel the throwing arm. A falling counterweight pulls down the bottom end of the arm and the projectile is thrown from a bucket attached to a rope hanging from the top end of the arm, essentially like a sling attached to a giant see-saw.
History
In Europe, the first catapults appeared in later Greek times (300 BC-400 BC), early adopters being Dionysius of Syracuse and Onomarchus of Phocis. Alexander the Great introduced the idea of using them to provide cover on the battlefield in addition to using them during sieges.
Catapults were more fully developed in Roman and Medieval times, with the trebuchet being introduced a relatively short time before the advent of gunpowder, which made the catapult obsolete.
See also
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