Leonardo da Vinci’s giant crossbow was a large weapon designed to launch heavy projectiles.
The drawing shows an oversized bow mounted on a wheeled frame. Leonardo increased the scale of the weapon to create a powerful psychological and military device, while using mechanical parts to draw back its bowstring. The broad frame also helped stabilize the machine during operation.
Leonardo developed many military designs for patrons who wanted stronger fortifications and more effective battlefield equipment. His notebooks include weapons, bridges, defensive structures, and machines for moving heavy materials.
The giant crossbow is often confused with Leonardo’s spring-powered catapult, but the mechanisms differ. A crossbow stores energy by bending a bow, whereas a catapult uses an arm and a spring or torsion system. Like many of Leonardo’s military machines, the giant crossbow is best known from drawings rather than documented battlefield use.