Leonardo da Vinci’s giant military crossbow was designed primarily to launch large stones.
Leonardo sketched the weapon around 1490 while developing military machines. Its enormous bow was mounted on a wheeled frame, and a mechanical system was intended to draw back the bowstring. The broad structure would have provided stability and allowed the weapon to be aimed across a battlefield.
The design was not an ordinary hand crossbow enlarged without limit. Leonardo’s notes and drawings show attention to leverage, winches, wheels, and the practical difficulty of bending such a large bow. The projectile was intended to be a large stone or similarly heavy missile rather than a standard arrow.
There is no evidence that Leonardo’s giant crossbow entered military service. Its value as an invention lies partly in its engineering study of stored elastic energy and mechanical advantage. Reconstructions have helped illustrate the concept, but they do not prove that the original design was fully workable.