What weapon did Leonardo da Vinci design with a single enormous bow and a wheeled frame?

Leonardo da Vinci designed a giant crossbow mounted on a wheeled frame.

Leonardo’s drawing, generally dated to the late 15th century, shows a huge bow mounted on a broad support structure. The machine included wheels and a mechanical system for drawing the bowstring, allowing the operator to generate more force than a person could manage with a handheld crossbow.

The design was intended as a siege weapon and psychological weapon as much as a practical artillery device. Its enormous scale would have made it difficult to build, transport, aim, and reload. No surviving evidence proves that Leonardo’s specific machine was constructed or used in battle.

It is commonly called Leonardo’s giant crossbow. It should not be confused with his multi-barrel weapons or his armored vehicle, which were separate military concepts.