Leonardo da Vinci designed an armoured tank with sloped armour and room for eight soldiers.
His fighting vehicle was drawn around 1487–1488, probably while he was seeking work from Ludovico Sforza, the Duke of Milan. The design resembles a low, conical turtle shell and was intended to move across a battlefield while protecting its crew from weapons fire.
The vehicle was to carry a crew of eight men and mount light cannons around its perimeter. Cranks connected to internal gears would turn the wheels. Sloping armour could help deflect incoming projectiles, an idea later associated with modern armoured vehicles.
A famous feature of the drawing is a suspected gear problem: the mechanisms appear arranged so that the vehicle could not move as shown. Some historians think this may have been deliberate, keeping the design from being easily copied or concealing a drafting error. No Renaissance tank was built from the plan.