Leonardo da Vinci arranged a cannon in multiple barrels for simultaneous firing.
Leonardo’s multi-barrel weapon is commonly associated with the organ gun, also called a volley gun. The design placed many small cannon barrels on a frame, allowing a volley of projectiles to be fired across a broad front. The arrangement resembled the pipes of a musical organ, which explains the name.
The concept addressed a major weakness of early gunpowder artillery: reloading individual weapons took time. A group of barrels could fire together or in sequence, giving defenders a dense burst of shot. Leonardo’s sketches also considered ways to move and aim the weapon, showing that he was thinking about battlefield logistics as well as the firing mechanism.
This was not a machine gun in the modern sense. Each barrel still required loading and preparation, and the weapon lacked automatic feeding or continuous fire. Similar multi-barrel weapons appeared elsewhere in military history, so Leonardo should not be credited with inventing every form of volley gun. His drawings are notable for applying systematic engineering to the problem of rapid fire.