Leonardo da Vinci designed an armored fighting vehicle commonly described as a tank.
His late-fifteenth-century design resembles a large conical tortoise. Sloped armor covered the vehicle, while a circular platform around its perimeter carried light cannons. Inside, men would turn cranks connected to wheels to move the machine across the battlefield.
The vehicle was never built for warfare in Leonardo’s lifetime. Its heavy armor and many guns made it visually impressive, but the proposed mechanism would have been difficult to operate. A famous drawing also appears to contain a gearing problem that would make the vehicle move backward unless corrected; historians debate whether this was an error or deliberate concealment.
Calling it a tank is modern terminology. Leonardo’s machine did not use the tracks, engine, or enclosed crew compartment associated with twentieth-century tanks, but it clearly belongs to the history of armored military vehicles.