Leonardo da Vinci sketched an armored tank-like fighting vehicle in 1487.
His design was a conical, turtle-shaped machine covered with metal plates. The sloping surfaces were intended to deflect incoming fire, while several light cannons projected through openings around the vehicle. Inside, men would turn cranks connected to wheels to move the machine across the ground.
The design appears in Leonardo’s manuscript work and is usually connected with his efforts to attract the patronage of Ludovico Sforza, Duke of Milan. It was a proposal for a military machine, not a completed vehicle used in battle.
Modern writers sometimes call it the first tank, but that label is retrospective. Leonardo’s machine had serious practical problems, including its heavy weight and the human power needed to drive it. Some versions of the drawing also contain a possible gearing error, though historians debate whether that was deliberate.