What rotating weapon did Leonardo da Vinci design with several rows of barrels?

Leonardo da Vinci designed a 33-barrel organ, a rotating weapon with several rows of barrels.

The device was a wheeled artillery platform carrying 33 small cannons arranged in three rows. The rows could be loaded and fired in sequence, allowing one row to cool while another was brought into position. A crank was intended to rotate the barrel assembly and adjust its angle.

The name “organ” refers to the visual arrangement of the barrels, which resembles the pipes of a musical organ. It was not a musical instrument. Leonardo’s proposal belongs to his military engineering studies and was never documented as a battlefield weapon successfully used by him. The design reflects a recurring Renaissance concern: increasing the rate of fire while limiting the delays caused by loading and overheating artillery.