Leonardo da Vinci sketched an organ gun as a multi-barrel firearm.
The weapon arranged many small cannons in rows or a fan-shaped formation, resembling the pipes of a musical organ. The layout was intended to fire several projectiles in a volley and then allow a fresh row to be brought into position while another was reloaded.
Leonardo’s design addressed a major weakness of early firearms: slow reloading. By distributing barrels across a frame, the weapon could potentially maintain more frequent fire than a single cannon, although it would still have been heavy, difficult to aim, and complicated to operate.
The organ gun was a design rather than a proven battlefield invention by Leonardo. Similar multi-barrel weapons existed in different forms, so it is safest to describe his drawing as an organ-gun concept rather than claim he originated every version of the weapon.