Leonardo da Vinci enlarged a crossbow dramatically in his giant crossbow design. He drew the weapon in the late 15th century as part of a group of military machines intended to impress and serve the Duke of Milan.
The design used a very broad bow mounted on a large wheeled frame. Leonardo’s notes and drawings focus on increasing the weapon’s throwing power while making it easier to load with a mechanical spanning device. The large frame also provided stability for the bow and its projectile.
The giant crossbow was a proposal rather than a documented battlefield success. Its scale made it difficult to transport and operate, and historians do not have evidence that Leonardo’s exact version was built and used in combat. It illustrates his recurring effort to combine weapon design with mechanical leverage.