What large weapon did Leonardo da Vinci sketch with a bow far wider than a person?

Leonardo da Vinci sketched a giant crossbow with an exceptionally wide bow.

The weapon was designed as a siege device rather than a handheld crossbow. Leonardo’s drawings show a large frame, wheels or supports, and a mechanism for drawing and releasing the bowstring. Its scale was intended to increase the projectile’s size and psychological impact.

Leonardo’s military notebooks contain many proposals for artillery, fortifications, bridges, and defensive machines. As with numerous designs in his codices, the giant crossbow is best understood as a documented concept; there is no reliable evidence that Leonardo built a fully operational example.

It is often confused with a ballista or a catapult. A crossbow stores energy in a bent bow and releases it through a string, whereas a catapult uses a throwing arm and a ballista is a distinct ancient torsion-powered weapon.