Leonardo da Vinci sketched an armored tank as a conical armored fighting machine powered by cranks.
His design, usually called Leonardo's fighting vehicle, appears in a drawing from around 1487–1490. The wooden vehicle had a broad, conical shell intended to deflect incoming missiles. Several men inside would turn cranks connected to the wheels, allowing the machine to move across a battlefield.
The tank was never built for Renaissance warfare, and its design contains a famous mechanical problem: the gears as drawn would make the wheels turn in opposing directions. Some historians think this may have been an intentional error to keep the design secret, while others regard it as a mistake.
The machine was not a modern tank with an engine, tracks, or metal armor. It was a speculative armored war wagon, but its enclosed protection and mobile firepower make “armored tank” the standard short answer. Leonardo also designed other military devices, including a giant crossbow and a multi-barrel cannon.