Pythagoras was a Greek philosopher and mathematician. He is best known for his contributions to mathematics, particularly the Pythagorean Theorem, and for founding the Pythagorean religion, whose adherents may have contributed some of the mathematical work that is often ascribed to him.
Historians believe Pythagoras was born on the island of Samos in 570 B.C., but little written information about him has survived. Most information about him comes from secondhand sources long after his death. It is believed that he may have traveled widely through Europe and Northern Africa in his youth, and it is known that he settled in Croton in 530 B.C. and formed the religion named after him. No direct writings by Pythagoras are known to exist. His followers Porphyry and Iamblichus left detailed writings about his school, but as they regarded Pythagoras as a divine figure, their historical accuracy is in question.
Because of the lack of written records, his actual contributions to mathematics and philosophy are unclear. The Pythagorean Theorem is attributed to him, though earlier records of this formula being used in Babylon and India exist. His followers may have completed the written proof of the theorem. Other developments made either by him or his followers were the invention of the tetractys, which is a symbolic arrangement of numbers, and investigations into the properties of string length in music.