Mathematician and Philosopher
Pythagoras is best known for the Pythagorean Theorem, a mathematical theorem which says c2 = a2 + b2. That is, in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the other two sides.
Religious and Philosophical Movement
Pythagoras established the Pythagorean Brotherhood at his academy in Crotone, Italy. This was a religious and philosophical movement that influenced Aristotle and Plato, and made an important contribution to the development of western philosophy. Pythagoras and his followers believed that everything was related to mathematics and everything could be predicted and measured in rhythmic patterns or cycles.
The Pythagoreans were vegetarians and believed in the transmigration of souls. They also, rather curiously, believed beans to be special and would not eat them. Pythagoras is said to have been killed by an angry mob when he refused to run through a bean field to escape their pursuit.
Background on Anne Rooney