Thales of Miletus (634-546 BC) -- from Eric Weisstein's World of Scientific Biography

Greek philosopher who is considered the founder of Greek science, mathematics, and philosophy. He visited Egypt and probably Babylon, bringing back knowledge of astronomy and geometry. He invented deductive mathematics. To him is attributed Thales

Thales of Miletus (634-546 BC) -- from Eric Weisstein's World of Scientific Biography