What machine did Leonardo da Vinci design to make a lion appear to walk and open its chest?

Leonardo da Vinci designed a mechanical lion that could appear to walk and open its chest.

The automaton was associated with a 1515 ceremony in Lyon, France, held for King Francis I. Contemporary accounts describe a lion that moved forward before opening its chest to reveal fleurs-de-lis, the royal emblem of France. The spectacle used mechanical motion and theatrical presentation to impress the court.

The original lion has not survived, and the exact mechanism is uncertain. It was probably driven by concealed clockwork or other mechanical components, with movement controlled in stages. Because the evidence is incomplete, reconstructions cannot be treated as exact copies of the original machine.

The lion is sometimes confused with Leonardo’s robotic knight, but the two automata served different purposes. The knight was a humanoid mechanical figure linked to Milan in 1495, while the lion was a ceremonial animal automaton associated with Francis I and France.