Heracleides of Pontus

Heracleides of Pontus was probably the first person to determine that the Earth rotates on its axis. He is also believed to have been the founder of heliocentrism.

He came from an aristocratic family. He studied at Plato's Academy in Athens, and Plato entrusted him with its administration for the duration of his third journey to Sicily in 360 BC. He was also a pupil of Aristotle and Speusippos, after whose death he sought the leadership of the Academy. This eventually fell to Xenocrates, and Heracleides returned to Heracleia.

As a philosopher, he wrote on ethics, rhetoric, mathematics, grammar and music. Unlike the Epicureans, he defended the immortality of the human soul. According to legend, he was also the author of plays, but these were published by more famous authors.