Born in Stagira in the northwestern region of the Aegean, Aristotle (384-322 B.C.) was the son of Nicomachus, a physician to the Macedonian king, Amyntas II. When he was eighteen, Aristotle left for Athens to study and became a member of Plato's Academy. He was in constant contact with Plato, teaching and studying until Plato's death. During the next twelve years, Aristotle taught and conducted research in biology, zoology, botany, and physiology in various places. It was during this period that he taught the boy who later became known as Alexander the Great. With his pedagogical activity at an end, Aristotle left for a time to Stagira, his native city, which Alexander rebuilt as a payment of debt to his teacher.

In 335 Aristotle returned to Athens. For the next twelve years he founded and directed a school, the Lyceum. It was also known as the “Peripatetic School,” since people studied while walking about. In 323 Alexander the Great died, and the reaction in Greece against Macedonian suzerainty led to a charge of impiety against Aristotle, who had been closely connected with the leader in his younger days. Aristotle left Athens, “lest the Athenians sin against philosophy a second time,” he said, a remark made in clear reference to Socrates. He went to Chalcis in Euboea, where he lived on an estate of his dead mother until he died in 322.