Leonardo da Vinci designed a 33-barrel organ, a frame holding many small cannons for repeated volleys.
The weapon arranged 33 barrels in rows or groups so one set could be fired while another was being loaded. The name “organ” refers to the visual resemblance between the parallel barrels and the pipes of a musical organ. Leonardo’s goal was to increase the rate of fire compared with a single cannon.
This was a proposal in his military notebooks, not a documented standardized weapon used by an army. The design is sometimes loosely labeled a machine gun, but that modern term can mislead: the barrels were not automatically fired, and the weapon still depended on manual loading and ignition.
Leonardo’s idea belongs to a period when engineers were experimenting with ways to make gunpowder artillery faster and more efficient.