The mangonel was a type of catapult that was invented by the Romans around 400BC as a light alternative to the ballista. The mangonel is not as accurate as the ballista, but is able to launch projectiles farther than the trebuchet. It can fire projectiles of up to 1300 ft. Mangonel is a term derived from the Latin word "manganon" which means "engine of war". It had one arm made out of timber and projectiles were launched at the end of the arm in a bowl-shaped bucket. This type of catapult was the easiest to make and sometimes had wheels added for extra maneuverability. The Onager was a type of mangonel catapult that used torsional force to store energy for the shot. The term Onager is derived from the term "onagros" which means "a wild ass".