Leonardos mechanical knight consisted of a suit of armor with a set of gears and pulleys inside designed to mimic human motion. Like his lion, the original knight has not survived, but a modern reconstruction has been made by Mark Rosheim. DaVinci's knight wasused for enternainment  for Lodovico Sforza and his guests. The knight likely would have been powered by springs or a waterwheel, and could have sat, stood, raised its visor, and moved its arms.

Image source: https://en.wikipedia.org/wiki/Leonardo%27s_robot

Erik Moller. Leonardo da Vinci. Mensch - Erfinder - Genie exhibit, Berlin 2005

Information Source: https://www.leonardodavinci.net/robotic-knight.jsp

No Author. "Robotic Knight - by Leonardo da Vinci." Leonardo da Vinci. Retrieved 8 March 2018

https://en.wikipedia.org/wiki/Leonardo%27s_robot

No Author. "Leonardo's robot". Wikipedia, The Free Encyclopedia. Retrieved 8 March 2018