Leonardo da Vinci designed a giant crossbow intended to launch oversized projectiles.
The weapon appears in Leonardo’s military sketches from the late fifteenth century. Its unusually large bow was mounted on a wheeled frame, and the design included mechanisms intended to draw the bowstring with substantial mechanical force. The scale was meant to create a powerful psychological and battlefield effect as well as a physical one.
Leonardo’s military notebooks contain many proposals that were never built or whose practical performance is unknown. The giant crossbow is therefore best described as an engineering design, not a confirmed battlefield weapon.
It is sometimes confused with ancient torsion artillery such as the ballista. A ballista used twisted cords to power its arms, whereas Leonardo’s design was a giant version of the familiar bent-bow crossbow principle.