The design notes for the robot appear in sketchbooks that were rediscovered in the 1950s. It is not known whether or not an attempt was made to build the device during da Vinci's lifetime. Since the discovery of the sketchbook, the robot has been built faithfully based on Leonardo's design; this proved it was fully functional, as Leonardo had planned.
The robot is a warrior, clad in German-Italian medieval armour, that is apparently able to make several human-like motions. These motions included sitting up, moving its arms, neck, and an anatomically correct jaw. It is partially the fruit of Leonardo's anatomical research in the Canon of Proportions as described in the Vitruvian Man.