Leonardo da Vinci designed a giant crossbow mounted on a wheeled frame.
The design appears in Leonardo’s studies of military engineering, where he explored ways to increase the psychological and physical impact of siege weapons. The enormous bow was intended to launch large bolts or stones, while the frame provided support and mobility.
Leonardo’s drawing emphasizes the weapon’s scale and mechanical tension rather than documenting a completed battlefield machine. A loading mechanism, including a winch-like arrangement, was needed because a bow of this size could not be drawn by ordinary human strength.
The giant crossbow is often confused with ancient torsion weapons such as the ballista. A ballista stores energy in twisted cords, whereas Leonardo’s concept uses a bow. Like many of Leonardo’s military projects, the design is best understood as an inventive proposal preserved in manuscript drawings, not as a confirmed operational weapon used by an army.