Xenophon of Athens (c. 430-354 BC) was an ancient Greek philosopher, historian, soldier, mercenary, and student of Socrates.As a historian, Xenophon is known for recording the history of his contemporary time, the late-5th and early-4th centuries BC, in such works as the Hellenica, about the final seven years and the aftermath of the Peloponnesian War (431-404 BC), a thematic continuation of Thucydides' History of the Peloponnesian War. As one of the Ten Thousand (Greek mercenaries), he also participated in Cyrus the Younger's failed campaign to claim the Persian throne from his brother Artaxerxes II of Persia and recounted the events in Anabasis, his most notable history.