Leonardo da Vinci’s giant crossbow was designed primarily to create fear on the battlefield. Its extraordinary size was meant to impress or intimidate an enemy as well as launch a large projectile, making psychological impact a central part of the concept.
Leonardo drew the weapon with a bow roughly 27 metres wide, a broad wheeled base, and a screw-driven system for pulling back the string. The wheels made the huge structure easier to reposition, while the mechanism supplied the force needed to cock it.
The design is often treated as if it were a completed superweapon, but the evidence is a set of Renaissance drawings. No surviving original proves that it entered combat. The crossbow therefore matters as an example of Leonardo combining engineering, spectacle, and military strategy in a single proposed machine.