What was Leonardo da Vinci’s large 1488 bow design called?

Leonardo da Vinci’s large 1488 bow design was called a giant crossbow.

The concept was a siege weapon intended to launch large stones or bolts. Leonardo’s drawing shows an enormous bow mounted on a wheeled frame, with a mechanism for drawing the bowstring. The frame would have helped support and reposition the weapon, while the broad limbs were meant to generate substantial force.

Leonardo prepared the design during his early Milanese period, when military engineering was central to his efforts to attract powerful patrons. The giant crossbow was not a normal handheld crossbow enlarged without limit; its scale required a crew, a supporting structure, and a method of tensioning the string.

The weapon is often confused with a ballista, an ancient torsion-powered missile weapon. Both could launch large projectiles, but Leonardo’s design is structurally based on a bow and string. There is no firm evidence that his giant crossbow was built or successfully fired. It remains a striking example of his interest in combining spectacle, mechanical force, and battlefield utility.