A trebuchet[nb 1] (French: trébuchet) is a type of catapult[3] that uses a long arm to throw a projectile. It was a common powerful siege engine until the advent of gunpowder. The design of a trebuchet allows it to launch projectiles of greater weights further distances than that of a traditional catapult.

Counterweight trebuchets at Château de Castelnaud
13th century depiction of Mongols using a counterweight trebuchet

There are two main types of trebuchets. The first is the traction trebuchet, or mangonel, which uses manpower to swing the arm. It first appeared in China in the 4th century BC. Carried westward by the Avars, the technology was adopted by the Byzantines in the late 6th century AD and by their neighbors in the following centuries.

The later, and often larger and more powerful, counterweight trebuchet, also known as the counterpoise trebuchet, uses a counterweight to swing the arm. It appeared in both Christian and Muslim lands around the Mediterranean in the 12th century, and was carried back to China by the Mongols in the 13th century.