Leonardo da Vinci’s giant crossbow was an enormous weapon design intended to fire a single large projectile.
Leonardo drew the design in the 1480s while working in Milan for Ludovico Sforza. The weapon had a very broad bow, a wheeled base and a mechanism for drawing and releasing the bowstring. Its extraordinary size was meant to increase range and create a powerful psychological effect as well as physical impact.
The drawing is commonly associated with Leonardo’s military-engineering work, which included fortifications, bridges and artillery studies. The giant crossbow was a design rather than a proven battlefield machine, and there is no firm evidence that Leonardo’s version was completed or used in war.
It is sometimes confused with Leonardo’s other large weapons, including his multi-barrel gun and giant catapult concepts. Those devices used different projectile systems. The giant crossbow remains notable because its huge scale shows Leonardo applying mechanical engineering to a familiar medieval weapon.