Leonardo da Vinci sketched a giant crossbow, an enormous siege weapon intended to launch a large projectile.
The design is usually dated to about 1488–1490, when Leonardo was developing military devices for powerful patrons in Italy. Its oversized bow was mounted on a broad wheeled frame, and the drawing shows a mechanism intended to draw the bowstring with mechanical assistance rather than human strength alone.
The giant crossbow was a proposal, not a documented battlefield weapon built and used by Leonardo. Its size has sometimes led people to call it a catapult, but the design is a crossbow because it uses a bow and string to propel the missile. Leonardo also drew other weapons, including multi-barrel guns and armored vehicles, which are separate inventions.