Pythagoras was a famous mathematician from Ancient Greece. Some even considered him to be the first pure mathematician. Pythagoras was born in about 569 BC in Samos, Ionia. It is said that Pythagoras was taught by some men in Chaldaeans and some men in Syria when he was young, but as a young man he was taught by three philosophers. The most important was probably Pherekydes. The other two philosophers that taught Pythagoras were Thales and Anaximander. Pythagoras went to Egypt in about 535 BC, here he learnt a bit about geometry. While Pythagoras was still in Egypt, Persia invaded and he was taken prisoner and taken to Babylon.

When he somehow got released he returned to Samos. Next Pythagoras traveled to Crete to study the system of laws there. When he finished, he founded a philosophical and religious school in Croton. Not much is known of Pythagoras’s work because his school was very secretive. Pythagoras studied the properties of numbers such as even and odd numbers and triangular numbers. Pythagoras believed that numbers had their own personality. For example, 10 was the best number, “it contained in itself the first four integers – one, two, three, and four [1 + 2 + 3 + 4 = 10] – and these written in dot notation formed a perfect triangle”.

Pythagoras had a lot of different theorems, here is a few of them.

1. The sum of the angles of a triangle is equal to two right angles.
2. The theorem of Pythagoras – for a right angled triangle the square on the hypotenuse is equal to the sum of the squares on the other two sides.
3. In astronomy Pythagoras taught that the Earth was a sphere at the centre of the Universe. He also recognized that the orbit of the Moon was inclined to the equator of the Earth and he was one of the first to realize that Venus as an evening star was the same planet as Venus as a morning star.

Pythagoras died in about 475 BC.

Reference:

http://www-groups.dcs.st-and.ac.uk/~history/Biographies/Pythagoras.html