Leonardo da Vinci’s armored vehicle concept for moving soldiers across a battlefield is commonly called Leonardo’s tank.
Leonardo designed the fighting vehicle around 1487 for Ludovico Sforza, the ruler of Milan. The machine had a conical, armored shell resembling a tortoise and was intended to carry weapons and soldiers. Its sloping armor could help deflect incoming attacks, while crews inside would turn cranks connected to wheels.
The vehicle is often called a tank because its broad concept resembles a protected military vehicle, but it was not a modern tank. Historians have noted that the surviving drawing appears to contain a mechanical problem: the gearing may be arranged so that the wheels would turn in opposite directions. Whether this was an error, an intentional concealment, or a later copying issue remains debated. No evidence shows that Leonardo’s vehicle was built in his lifetime.