Leonardo da Vinci’s 33-barrel organ used multiple barrels to fire a rapid volley of cannon shot.
The weapon consisted of 33 small-caliber gun barrels arranged in three rows on a wheeled frame. The rows could be loaded or fired in sequence, allowing one group to cool while another was used. Leonardo’s arrangement was intended to improve the speed and continuity of artillery fire compared with a single muzzle-loading cannon.
The name organ comes from the visual resemblance between the parallel barrels and the pipes of a musical organ. It was not a musical instrument. The weapon is also commonly called a multiple-barrel cannon or a volley gun, but “33-barrel organ” is the distinctive name associated with Leonardo’s design.
As with many of Leonardo’s military machines, there is no evidence that the original device entered regular battlefield service. The concept nevertheless anticipates later attempts to combine many barrels for concentrated fire, including volley guns and other forms of early rapid-fire artillery.