What oversized weapon did Leonardo da Vinci design with a bow far larger than a person?

Leonardo da Vinci designed a giant crossbow intended as a powerful siege weapon.

Leonardo drew the oversized crossbow around 1488–1489 while working on military engineering projects. Its enormous bow was mounted on a wheeled frame, and the design included a mechanism for drawing the string back. The scale was meant to increase the weapon’s psychological impact as well as its range and destructive power.

The design is usually called Leonardo’s giant crossbow, although historians cannot prove that a full-size working example was built in his lifetime. Large siege crossbows already existed before Leonardo, so his contribution was an imaginative redesign rather than the invention of the crossbow itself.

Modern reconstructions show how difficult such a machine would have been to operate. The surviving drawing is valuable because it reveals Leonardo’s habit of combining weapon design with careful studies of force, leverage, and construction.