Leonardo da Vinci’s organ gun used 33 small cannons arranged on a rotating platform.
Leonardo’s design placed multiple gun barrels in three rows, allowing one row to fire while the others were reloaded or cooled. The arrangement resembled the pipes of a musical organ, which explains the name commonly associated with this type of weapon.
The proposal was intended to increase the speed and continuity of artillery fire. Leonardo’s military notebooks contain several weapons concepts, but surviving drawings do not prove that this particular 33-barrel design was constructed or used in battle.
An organ gun is different from a modern machine gun. It relied on separate cannon barrels and the technology of Renaissance black-powder artillery, rather than a self-loading mechanism. Leonardo also designed other large weapons, including a giant crossbow, so the two concepts should not be treated as the same machine.