(born c. 580 BC, Samos, Ioniadied c. 500, Metapontum, Lucania) Greek philosopher and mathematician. He established a community of followers in Croton who adhered to a way of life he prescribed. His school of philosophy reduced all meaning to numerical relationships and proposed that all existing objects are fundamentally composed of form and not material substance. The principles of Pythagoreanism, including belief in the immortality and reincarnation of the soul and in the liberating power of abstinence and asceticism, influenced the thought of Plato and Aristotle and contributed to the development of mathematics and Western rational philosophy. The proportions of musical intervals and scales were first studied by Pythagoras, and he was the first influential Western practitioner of vegetarianism. None of his writings survive, and it is difficult to distinguish the ideas he originated from those of his disciples. His memory is kept alive partly by the Pythagorean theorem, probably developed by his school after he died.