Leonardo da Vinci drew an organ gun with multiple barrels arranged in rows.
An organ gun is a volley weapon made from several small gun barrels mounted together. Leonardo’s version placed the barrels on a wheeled frame, allowing a group of shots to be fired in succession or as a concentrated volley. The name comes from the resemblance of the barrel rows to the pipes of a musical organ.
The design addressed a major weakness of early gunpowder weapons: slow reloading. While one row was being prepared, another could potentially be used, increasing the rate of fire compared with a single cannon.
Leonardo’s drawing does not prove that he built or deployed the weapon. It is also not a machine gun in the modern sense, because it lacked automatic loading and continuous powered firing.