What armored vehicle did Leonardo da Vinci design for battlefield movement?

Leonardo da Vinci designed an armored tank, a covered fighting vehicle intended to move across a battlefield.

His famous drawing, generally dated to about 1485, shows a conical, turtle-like armored shell mounted on wheels. The vehicle was intended to protect occupants while they operated a group of guns through openings around its perimeter. A crew inside would turn cranks connected to the wheels.

The design is often called Leonardo’s tank, but it was never built for a fifteenth-century battle. A commonly discussed problem is that the wheel arrangements in the surviving drawing appear mechanically inconsistent: some interpretations suggest the design may contain an intentional error or may simply reflect an unfinished plan.

Leonardo’s concept predates modern tanks by more than four centuries. Modern tanks combine armor, engines, tracks, and a turret, whereas Leonardo’s proposal relied on human-powered wheels and fixed firing positions.