Leonardo da Vinci arranged 33 small cannons in three rows in an organ-gun design.
The weapon was intended to fire a coordinated volley. Its many short barrels were arranged like the pipes of a musical organ, which explains the name. A wheeled frame could be positioned on the battlefield, while successive rows were meant to provide repeated fire as the weapon was operated.
Calling it a machine gun is a modern shortcut. Leonardo’s concept did not have the automatic loading, cartridge ammunition, or continuous firing mechanism associated with modern machine guns. It was better understood as a multi-barrel volley weapon.
The design addressed a practical artillery problem: conventional cannons took time to reload. By grouping many barrels together, Leonardo sought to increase the volume of fire, although the machine would still have been heavy and difficult to handle.