Leonardo da Vinci’s repeating-gun design arranged multiple barrels in a fan-like formation and is commonly called an organ gun.
The name comes from the resemblance between the grouped barrels and the pipes of a musical organ. Leonardo’s military sketches show rows of small cannon that could be loaded and fired in sequence. The arrangement was intended to increase the rate of fire compared with a single muzzle-loading gun.
The design was not a machine gun in the modern sense. Each barrel still required loading, and the weapon’s operation depended on the period’s gunpowder technology. It also had the practical disadvantages of weight, smoke, recoil, and the time required to prepare the barrels.
Organ guns existed in several forms and were used by different armies, so Leonardo did not invent every weapon later given that name. His drawings are notable for combining many barrels into a coordinated battlefield weapon. The concept belongs to the long history of volley firearms, which later included larger and more sophisticated systems.