Which Leonardo da Vinci machine was a mechanical lion that could open its chest?

Leonardo da Vinci designed a mechanical lion that could open its chest.

The automaton was reportedly created for a diplomatic spectacle in the early sixteenth century. Historical accounts connect it with celebrations held for King Francis I of France, although the surviving evidence is limited and the original mechanism has not survived. Descriptions say that the lion walked or moved forward and then opened its chest to reveal fleurs-de-lis, the heraldic symbol of the French monarchy.

The machine belongs to Leonardo’s broader work on automata, theatrical devices, and mechanical motion. Its exact construction is uncertain because no complete original drawing or preserved machine establishes every detail. Modern reconstructions therefore combine Leonardo’s known mechanical methods with the surviving descriptions.

The lion is often confused with Leonardo’s mechanical knight, which was a human-shaped automaton. The lion instead functioned as a symbolic court spectacle, using movement and a dramatic opening mechanism to communicate a political message. It illustrates how Leonardo’s engineering served both entertainment and ceremony.