Background: One might assume from the title of this paper that the nuances of a complex mechanical robot will be discussed, and this would be correct. On the other hand, the date of the design and possible construction of this robot was 1495, a little more than five centuries ago. The key point in the title is the lack of a trademarked name, as Leonardo was the designer of this sophisticated system. His notes from the Codex Altanticus represent the foundation of this report.

Methods: English translations of da Vinci's notebooks are currently available. Beginning in the 1950s, investigators at the University of California began to ponder the significance of some of da Vinci's markings on what appeared to be technical drawings. Such markings also occur in his Codex Atlanticus (the largest single collection of da Vinci's sheets, consisting of 1119 separate pages and 481 folios) along with a large number of other mechanical devices. Continuing research at the Instituto e Museo di Storia della Scienza in Florence has yielded a great deal of information about Leonardo's intentions with regard to his mechanical knight.

Results: It is now known that da Vinci's robot would have had the outer appearance of a Germanic knight. It had a complex core of mechanical devices that probably was human powered. The robot had two independent operating systems. The first had three degree-of-freedom legs, ankles, knees, and hips. The second had four degrees of freedom in the arms with articulated shoulders, elbows, wrists, and hands. A mechanical analog-programmable controller within the chest provided the power and control for the arms. The legs were powered by an external crank arrangement driving the cable, which connected to key locations near each lower extremity's joints. Da Vinci also is known to have devised a programmable front-wheel-drive automobile with rack-and-pinion suspension mechanisms at age 26. He would recall this device again, when, at age 40, he is thought to have built a programmable automated lion, but by then, he had produced his own metal springs as well as drum-containing springs called tambours. He positioned his fusee to a stationary rotating power output shaft that would be used to power his programmable automaton.

Conclusions: Part of the obscurity of da Vinci's robot comes from the difficulties interpreting Leonardo's markings. His designs precede any formal method of blueprint designing. The technical aspects had to be deciphered before anyone could even attempt to reproduce his intended device. This robotic device fits together with other pieces of evidence that link 15(th) Century automatons to da Vinci's design, namely the automated Tea Servers from Spain. As with many things from da Vinci, looking backward at this master leaves one with a pronounced sense of awe at his prescient view of the world.