Which Leonardo da Vinci design is commonly described as an early armoured fighting vehicle?

Leonardo da Vinci’s tank is a conical armoured fighting-vehicle design driven by internal cranks.

Leonardo designed the vehicle in the late 15th century, probably for presentation to Ludovico Sforza, duke of Milan. Its sloped, conical shell was intended to deflect enemy fire, while a crew inside would turn cranks connected to wheels. The vehicle also included numerous guns arranged around its perimeter.

The design was not a battlefield tank and was never deployed by Leonardo. A famous drawing appears to contain a mechanical flaw: the proposed gears would make the wheels turn in opposite directions. Some historians suggest this may have been deliberate, hiding the design from casual readers or preventing others from using it immediately.

Modern reconstructions have shown that modified versions can move, but they do not prove that Leonardo’s original machine was operational. The design is historically significant because it combines armour, mobility, and concentrated firepower in one concept.