Born in Stageira in the north of Greece, Aristotle moved to Athens at the age of seventeen and became a student of Plato. He lived in Athens for twenty years, leaving in 347, the year of Plato's death. He settled first in Assos, where he joined a group of philosophers. There he married Pythias, the niece of Hermeias, the leader of the nearby city of Atarneus. Hermeias supported the work of the philosphers in Assos, but when he was assassinated in 340, Aristotle fled to the island of Lesbos and taught in Mytilene for a few years.
In 342, Aristotle accepted the invitation of Philip II to tutor the king's young son Alexander. Alexander assumed the throne in 335, and Aristotle returned to Athens and began a career teaching in what became known as the Lyceum. He founded the first major library and research center of the ancient world.
When Alexander died in 323, anti-Macedonian sentiments in Athens made Aristotle's life uncomfortable. He moved to Chalcis in Euboea, where he died in the following year.
Although a relatively small portion of Aristotle's body of philosophical work has survived, the influence of his thought on Western philosophy has been enormous.