What weapon did Leonardo da Vinci design with a huge bow for launching giant arrows?

Leonardo da Vinci designed a giant crossbow for launching exceptionally large arrows.

Leonardo’s drawings show the weapon mounted on a broad platform, with a bow far larger than an ordinary handheld crossbow. The design included wheels and a mechanical winding system, allowing the bowstring to be drawn with greater force than a person could produce directly.

The giant crossbow belongs to Leonardo’s military-engineering work in Renaissance Italy. He presented many ideas to powerful patrons as possible siege or battlefield technologies, although there is no reliable evidence that this particular machine was built and used in combat.

It is sometimes confused with a ballista, a classical torsion weapon that launched bolts. Leonardo’s design used the characteristic bow-and-string mechanism of a crossbow, simply enlarged to an impractical-looking scale.