Leonardo da Vinci designed a giant crossbow mounted on a wheeled platform.
The drawing appears in the Codex Atlanticus and dates from the late fifteenth century. Leonardo envisioned an enormous bow supported by a broad frame, with wheels that could help move the weapon and a mechanical system for drawing the bowstring. The design was intended to intimidate an enemy as well as launch a large projectile.
The crossbow was not a practical battlefield weapon in the form shown. Its massive size created serious problems involving transport, construction, tension, and reloading. Leonardo’s interest lay partly in improving the power and visual impact of existing siege weapons.
This machine is often confused with a catapult or ballista. A crossbow stores energy by bending a bow, whereas a catapult or trebuchet throws a projectile using a swinging arm or counterweight. Leonardo’s drawing clearly belongs to the crossbow family.