Pythagoras (582?-500?) was a Greek philosopher who was active about 530 B.C. Scarcely anything is known of Pythagoras' early life, but it is believed that he was born on the island of Samos.
   He was important for having worked out a method of proving what is now known as the Pythagorean theorem. This theorem states that the square of the hypotenuse of a right-angled triangle is equal to the sum of the squares of the other two sides.