What Leonardo da Vinci design is considered an early concept for a robot knight?

Leonardo da Vinci's robotic knight is an early concept for a humanoid automaton. He designed it around 1495 for a pageant in Milan, probably under the patronage of Ludovico Sforza.

The knight was enclosed in armor and operated by cables, pulleys, and a system of levers. According to surviving sketches and reconstructions, it could sit, stand, raise its arms, and move its head and jaw. Leonardo based the mechanism partly on his anatomical studies of human joints and muscles.

The original machine disappeared, and its existence was uncertain until engineers examined Leonardo's notebooks in the twentieth century. In 2002, roboticist Mark Rosheim built a working model from the drawings. A larger, more complete reconstruction was later displayed in Milan.

It was not an autonomous robot in the modern electronic sense. It was a mechanically programmed automaton, powered by human winding and constrained to a limited set of movements.