Pythagoras (peh-THAG-eh-ruhs) was the son of a Samian merchant and traveled extensively, studying as a youth in Tyre with the Chaldeans and Syrians and later in Miletus (Ionia) with the scientist-philosophers Thales of Miletus (possibly) and Anaximander. Subsequently, he went to Egypt, where he studied geometry and immersed himself in the mystical rites of the Diospolis temple. Taken from Egypt as a Persian prisoner-of-war, he continued his studies with the Magoi in Babylon, both absorbing their religion and perfecting his knowledge of mathematics and music. He returned to Samos, where he established his first society of mystic mathematician-philosophers, the “semicircle of Pythagoras.”
In response to political turmoil and resistance to his teachings, he moved to Croton, off the coast of Italy. There he founded a secret philosophical and religious school including both men and women. The inner circle (mathematikoi) were expected to exercise strict physical and mental discipline, live communally, eat no meat, and wear no animal skins. Pythagoreans studied mathematical relationships, mathematical abstractions, and the concept of number as well as more mystical and spiritual subjects such as the belief in perfection through the transmigration of souls (hence their reverence for animals) and spiritual purification through intellect and discipline. He fled to Metapontum, again to escape political turmoil and attacks on his school. Some evidence exists that he may have returned to Croton before his death.
As a result of his studies of music, mathematics, and astronomy, Pythagoras believed that the entire cosmos could be reduced to scale and numbers; reality was mathematical in nature and everything could be expressed in mathematical terms. He believed that certain symbols had mystical significance and that numbers had personalities. He described the “music of the spheres” and taught that the earth was the center of the universe and that celestial bodies moved in circular orbits. He noted that Venus was both the morning and evening star and that the Moon inclined to the equator. He also believed the brain was the locus of the soul and contributed to the mathematical theory of music when he discovered that tones and harmonies were ratios of whole numbers. He (or his school) developed a number of mathematical theorems, but he is best remembered for the Pythagorean theorem, an ancient idea in Babylon but one that he was able to prove.