What armored fighting vehicle did Leonardo da Vinci design with a conical shell?

Leonardo da Vinci designed an armored tank-like fighting vehicle with a conical shell.

Leonardo drew the vehicle in the 1480s while working for Ludovico Sforza in Milan. Its sloping, conical cover was intended to deflect enemy projectiles, and the vehicle was shown with multiple light cannons arranged around its perimeter. Crews inside would turn wheels connected to the vehicle’s mechanisms, allowing it to move across a battlefield.

The design is often called Leonardo’s tank, although it predates the modern tank by centuries and was never documented in combat. One famous drawing appears to contain a mechanical inconsistency: the gear arrangement seems to make the vehicle move backward when the operators turn the handles in the intended direction. Some historians think this may have been an error; others have suggested that Leonardo deliberately concealed or altered details.

The vehicle was a design study, not a proven prototype. Its armored body, internal crew space, and gun ports nevertheless make it one of the clearest early concepts resembling a tank.