Leonardo da Vinci sketched an armored tank with sloping armor and several cannons arranged around its sides.
The fighting vehicle appears in Leonardo's notebooks from the late fifteenth century. Its conical, turtle-like cover was intended to protect the crew, while guns placed around the perimeter could fire in multiple directions. The machine was shown with wheels and internal mechanisms for movement.
Leonardo's design was not a modern tank in the technical sense. It lacked an engine and would have required people inside to turn cranks. A commonly repeated claim says the vehicle contained a deliberate gear error to prevent an employer from using it, but historians have not established that explanation as fact.
The vehicle was never built by Leonardo and did not enter military service. It nevertheless demonstrates his interest in combining armor, mobility, and all-around firepower. Modern reconstructions have shown that the design can be made to move after its mechanism is adjusted.