Leonardo da Vinci designed an armored tank-like fighting vehicle with sloping armor and several cannons.
His drawing, usually dated to about 1487–1489, shows a covered conical vehicle resembling a turtle. The sloped armor was intended to deflect incoming projectiles, while a ring of light cannons projected through openings around the vehicle. The machine would be moved by people turning internal cranks connected to wheels.
Leonardo’s fighting vehicle was never built for Renaissance warfare. A commonly discussed problem is that the crank arrangement in the drawing would make the wheels turn in conflicting directions, possibly because of an intentional error or an unfinished design. The vehicle also would have been difficult to move over rough ground.
Calling it a modern tank is convenient but approximate. It had armor, mobility, and guns, yet lacked the engine, turret, and tracked system associated with twentieth-century tanks.