Which Leonardo da Vinci invention used 33 small-caliber guns arranged in three rows?

Leonardo da Vinci’s 33-barrelled organ used 33 small-caliber guns arranged in three rows.

The weapon was designed to improve the practical firing rate of artillery. Instead of loading one barrel repeatedly, crews could fire a row while the other rows were prepared. The gun assembly resembled the pipes of an organ, which explains the name commonly given to the design.

Leonardo’s surviving sketches show the barrels mounted on a wheeled frame. The arrangement was intended to be moved and aimed more easily than a single large cannon, while multiple shots could create a concentrated volley.

The 33-barrelled organ should not be confused with a modern organ gun or with Leonardo’s armored fighting vehicle. Like many of his military designs, it survives mainly as a drawing and proposal rather than as a documented battlefield weapon.