Pythagoras (582?-500? BC), was a Greek philosopher and mathematician, whose doctrines
strongly influenced Plato. Among the extensive mathematical investigations carried on by Pythagoras
and his followers was the study of odd and even numbers and of prime and square
numbers. Through such studies they established a scientific foundation for
mathematics. In Geometry their great discovery was the hypotenuse theorem, or Pythagorean theorem,
which states that the square of the hypotenuse of a right triangle is equal to the
sum of the squares of the other two sides. The astronomy of the Pythagoreans
marked an important advance in ancient scientific thought, for they were the
first to consider the earth as a globe revolving with the other planets around a
central fire (see Sun).