Leonardo da Vinci designed a 33-barrel organ with three rotating rows of guns. The weapon arranged 33 small cannons on a frame that could be aimed, fired, and repositioned more efficiently than a single line of artillery.
The design is commonly called a “33-barrel organ” because its parallel gun barrels resemble the pipes of a musical organ. Its rotating arrangement was intended to allow one row to fire while another cooled and a third was loaded. That proposed cycle addressed the slow reload time of early gunpowder weapons.
The weapon was not a modern machine gun. It fired separate cannon barrels and depended on manual loading, aiming, and ignition. Leonardo’s drawings show the concept, but surviving evidence does not prove that a complete 33-barrel example was built and used in battle.