What did Leonardo da Vinci’s robotic knight have inside its torso?

Leonardo da Vinci’s robotic knight had gears and pulleys inside its torso.

Leonardo designed the mechanical knight around 1495 for a pageant at the court of Ludovico Sforza in Milan. The armor-covered figure was intended to sit, stand, move its arms, and operate its jaw through an internal system of cables, gears, and pulleys.

The machine is known from Leonardo’s notebooks rather than from a surviving original. In 2002, roboticist Mark Rosheim built a working reconstruction based on the drawings. The reconstruction helped show that the mechanism could produce the movements Leonardo described, although claims about exactly how the original performed should be treated cautiously.