This guy lived around 570 to 495 BC in Greece and he is known to be the founder of the Pythagorean group. That group was known to be one of the first to study advance mathematics. I am pretty sure that you guys are familiar with the Pythagoras Theorem, the one used in trigonometry. Well, this guy came up with that rule. There are theories that state that it was not him that came up with that equation. Considering of course that he did, it was remarkable contribution to the world of mathematics. That’s what opened the door to the study of geometry.