Leonardo da Vinci designed a giant crossbow with a very large bow mounted on a wheeled frame. The drawing presents an oversized siege weapon intended to intimidate opponents and launch a large projectile.
Leonardo developed the design in the late 15th century while seeking military commissions from powerful Italian patrons. Its bow was shown as extremely broad, and the machine included a mechanism for drawing the string and a supporting carriage. The wheels would have helped move the weapon and stabilize it during operation.
The giant crossbow is sometimes confused with a medieval ballista, because both use tension to propel a missile. Leonardo’s drawing, however, is identified specifically as a giant crossbow and reflects his interest in scaling familiar weapons into dramatic battlefield machines.
There is no reliable evidence that Leonardo’s oversized design was built and used in combat. Like many of his military sketches, it survives primarily as an engineering concept in his notebooks.