Foundations of Geometry

It has been known for some time that the Pythagorean Theorem did not originate with Pythagoras. He is credited, however, with having given the first proof thereof— a credit not in serious doubt as far as Western mathematics is concerned¹. There are other early proofs from China and India, with the Chinese claiming priority by a period of time that is not determined too exactly by the references at hand.² But, except for ethnic bragging rights— and I am neither Greek nor Chinese nor Hindi— the earliest authorship is unimportant. What I wish to discuss is not the original discoverer of the proof, but the original proof and form of the result.