What armored vehicle did Leonardo da Vinci sketch for battlefield use?

Leonardo da Vinci sketched an armored vehicle for battlefield use, commonly called Leonardo’s tank.

The vehicle appears in a drawing from the 1480s and has a conical, turtle-like armored shell. Its sloping armor was intended to deflect incoming projectiles. Leonardo’s plan placed guns around the vehicle so it could fire in several directions while protecting the crew inside.

The design was to be moved by people turning cranks connected to wheels. A commonly noted problem is that the crank and wheel arrangement shown in the drawing would move in conflicting directions, so the vehicle could not operate exactly as depicted. Some historians think this may have been deliberate, since Leonardo sometimes concealed military designs or introduced flaws into presentation drawings.

Calling it a “tank” is modern shorthand. Leonardo’s machine was not a modern tracked tank, and there is no evidence that it was built or used in battle.