Leonardo da Vinci’s armored vehicle design is commonly called Leonardo’s tank.
Leonardo designed the fighting vehicle around 1487–1489, probably while seeking military patronage from Ludovico Sforza in Milan. The machine had a conical, turtle-like protective shell and a ring of light cannons projecting through openings. Inside, men were supposed to turn cranks connected to wheels, allowing the vehicle to move across the battlefield.
The design is frequently described as an early tank because it combined armor, mobile firepower, and crew protection. However, it was never built for Renaissance warfare, and Leonardo’s surviving drawing contains a mechanical problem: the gears as shown would cause the wheels to turn in opposite directions. Some historians think the flaw may have been deliberate, hiding the design from rivals.
The vehicle was also too heavy for practical movement with the proposed human power. Modern reconstructions can move after modifying the gearing, but they demonstrate Leonardo’s concept rather than an operational fifteenth-century tank.