Leonardo da Vinci is commonly credited with designing an armored fighting vehicle often called a tank.
His drawing shows a conical, turtle-like armored vehicle with sloping protective plates and several cannons around its perimeter. Inside, men would turn cranks connected to gears to drive the vehicle's wheels. The machine was intended to enter enemy formations while shielding its crew from weapons fire.
The design is usually dated to about 1487 and is associated with Leonardo's military engineering work for Ludovico Sforza in Milan. It was never built for Renaissance warfare. Some versions of the drawing appear to contain a gearing problem that would make the vehicle move backward, though historians debate whether this was deliberate or an error.
Calling it a tank is a modern comparison, not Leonardo's own name. Modern tanks use engines, tracks, and different weapons, while Leonardo's proposal relied on human power and wheels.