In Stephen Hawking's book "The Grand Design" he states that "Pythagoras probably did not discover this - he also did not discover the theorem that bears his name" ... if not Pythagoras then who?

Asked by talljasperman (21916) March 10th, 2011

from page 19 “The Grand Design”
... what else are we taught that isn’t really true? Who discovered “The Pythagoras Theorem?”