Leonardo da Vinci’s giant crossbow is a massive siege-weapon design intended to launch unusually large projectiles. It appears among his military engineering studies from the late 15th century.
The bow was drawn on a broad wheeled frame, with a central mechanism used to bend the prod. Leonardo emphasized intimidation as well as force: the oversized weapon would have had a dramatic psychological effect on an enemy. Its wheels were meant to help transport and position the structure.
Despite detailed drawings, there is no evidence that Leonardo’s giant crossbow entered service. Reconstructions show that its scale creates major problems involving stored energy, structural strength and accurate release. It should not be confused with a classical ballista, which used a different torsion-powered mechanism rather than a giant flexing bow.