A shadowy figure, principally known from some disputed fragments and mention by Plato and Aristotle. He is regarded as an important transmitter of Pythagorean cosmology and mathematics to mainland Greece. He is mentioned in Plato’s Phaedo as arguing that suicide is not permissible, and a primary source for Aristotle’s account of Pythagoreanism. His cosmology also influenced Plato’s Philebus; and he was the first Greek thinker to make the earth a planet.