Leonardo da Vinci’s armored military vehicle with a conical shell is commonly called Leonardo’s tank.
Leonardo designed the fighting vehicle around 1487 for Ludovico Sforza, the ruler of Milan. Its sloped outer shell was intended to deflect enemy fire, while guns placed around the platform could fire in several directions. The vehicle was to be moved by people turning cranks connected to wheels.
The design was never built for Renaissance warfare, and it was not a tank in the modern technical sense. Modern tanks use engines, tracks, armor systems, and internal crew arrangements that did not exist in Leonardo’s proposal. The familiar name is a later comparison based on its armored, mobile fighting role.
A famous drawing appears to show a mechanical flaw: the proposed gear arrangement would make the wheels turn in conflicting directions. Some historians suggest this may have been an intentional error to prevent the design from being used, but that explanation is not proven. The secure fact is that Leonardo drew an armored fighting vehicle with multiple guns.