Leonardo da Vinci sketched an armored vehicle commonly described as a tank.
His design, drawn around 1487, was a conical, turtle-like vehicle covered with metal plates. Sloping armor was intended to deflect enemy fire, while several small cannons projected through openings around the platform. The vehicle would have been moved by people turning cranks connected to internal wheels.
The machine was never built for Leonardo's patron, Ludovico Sforza, and it was not a practical modern tank. Its proposed crew would have struggled to operate the gears, and the vehicle was extremely heavy. A famous drawing also appears to contain a gearing problem that would make the mechanism move backward unless corrected.
The tank label is a modern comparison, not Leonardo's own term. He designed many military machines, including bridges, weapons, and siege devices, but this armored vehicle is his best-known land-combat concept.