Leonardo da Vinci designed a giant crossbow mounted on a wheeled frame as a powerful siege weapon.
The design appears in Leonardo’s engineering studies from the late 15th century. Its enormous bow was supported by a broad carriage, while a mechanical winding system would have drawn back the string. The wheels were intended to help position the machine and possibly improve its stability.
The giant crossbow is generally understood as a proposal rather than a weapon that Leonardo successfully built and tested. Reconstructions have been made from his drawings, but they should not be treated as surviving original artillery. The machine is also called a giant crossbow or gigantic crossbow, not a standard handheld crossbow.
Leonardo’s military sketches included weapons, fortifications, bridges, and devices for moving troops. His designs often emphasized mechanical force and practical deployment, even when their scale made construction difficult.