Which military weapon did Leonardo da Vinci design with a very large bow?

Leonardo da Vinci designed a giant crossbow as a military weapon intended to launch large projectiles.

The design appears in Leonardo’s Codex Atlanticus and was probably conceived in the late fifteenth century. Its enormous bow was mounted on a wheeled platform, and the machine included a mechanism for drawing the bowstring. Leonardo emphasized the weapon’s intimidating size and potential range as well as its projectile power.

The giant crossbow was a proposal rather than a confirmed battlefield weapon. No evidence shows that Leonardo’s exact machine was manufactured and successfully used in war. Drawings of the device reveal his habit of combining engineering analysis with dramatic presentation when proposing military technology.

It is distinct from his armored vehicle, which used a conical shell and internal mechanisms. It is also different from ancient ballistae and catapults, which used other launching principles.