Leonardo da Vinci’s 33-barrel weapon was an organ gun.
Leonardo designed the organ gun, also called a triple-barrelled cannon, as a rapid-firing artillery concept. Its 33 small gun barrels were arranged in three rows on a wheeled frame. The arrangement was compared to the pipes of an organ, which explains the name. A crew could fire one row while another was being loaded, at least in theory.
The weapon belonged to Leonardo’s broader work on military engineering during the Renaissance. His notebooks contain designs for artillery, fortifications, bridges, and armored vehicles. The organ gun was a paper design rather than a clearly documented weapon that entered regular service.
The number 33 is especially useful for distinguishing the organ gun from Leonardo’s other military sketches. It should not be confused with the armored fighting vehicle often called his tank, which used a conical body and internal cranks instead of multiple gun barrels.