What military vehicle did Leonardo da Vinci sketch with sloping armor and many cannons?

Leonardo da Vinci sketched an armored vehicle with sloping armor and multiple cannons.

The design, usually dated to about 1487, resembles a broad, conical or turtle-like covered platform. Small cannons project through openings around its perimeter, while a crew inside would turn cranks connected to gears and wheels. The sloping exterior was intended to deflect incoming projectiles and protect the operators.

Modern popular culture often calls it Leonardo’s tank. That label is understandable because the vehicle is armored and mobile, but it was not a modern tank: it had no engine, turret, continuous tracks, or demonstrated battlefield history. The surviving design also contains a famous mechanical problem. If the gears were arranged exactly as drawn, the wheels would tend to turn in conflicting directions, although some historians suggest this may have been an intentional error or a copying issue.

No evidence shows that Leonardo’s vehicle was built or used in war. It remains a striking example of Renaissance military engineering imagination.