What Leonardo da Vinci siege weapon had a very large single bow?

Leonardo da Vinci’s giant crossbow was a siege weapon with an exceptionally large single bow. He designed it in the late fifteenth century as a dramatic artillery device for warfare.

The machine was intended to launch large bolts or stones and was shown with a broad wooden frame, wheels and a mechanism for drawing back the bow. Leonardo’s drawings emphasize scale and mechanical force. The crossbow’s size would have made it difficult to build, transport and operate, and there is no reliable evidence that Leonardo’s design was successfully constructed for battle.

The giant crossbow is not the same as a ballista or a later gunpowder cannon. A crossbow stores energy by bending a bow, while a cannon uses an explosive propellant. Leonardo produced several military designs for patrons, including fortifications and weapons, but many remained conceptual rather than tested inventions.