Leonardo da Vinci’s armored military vehicle is commonly called Leonardo’s tank.
Leonardo designed the fighting vehicle around 1487 for the court of Ludovico Sforza in Milan. The vehicle had a conical, turtle-like armored shell made from angled plates. Inside, men would turn cranks connected to wheels, allowing the machine to move while protecting its crew from enemy fire. Small guns were intended to project through openings around the vehicle.
The design was not built as a fifteenth-century battlefield vehicle. Some modern discussions point out that the surviving drawing appears to contain a mechanical inconsistency: the gears would make the wheels turn in opposite directions. Whether this was an error, a deliberate safeguard, or a copying issue remains debated. The machine is therefore best treated as a design concept, not a working tank.