Xenophon of Athens was an ancient Greek philosopher, historian, soldier, mercenary, and student of Socrates. As an 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 ; as such, the Hellenica is a thematic continuation of Thucydides' History of the Peloponnesian War. As one of the Ten Thousand , 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. Like Plato , Xenophon is an authority on Socrates, about whom he wrote several books of dialogues and an Apology of Socrates to the Jury, which recounts the philosopher's trial in 399 BC.
Despite being an Athenian citizen, born to Gryllus, of the deme Erchia of Athens, Xenophon was also associated with the city-state of Sparta, the traditional enemy of Athens'. His pro-oligarchic politics, military service under Spartan generals, in the Persian campaign and elsewhere, and his friendship with King Agesilaus II endeared Xenophon to the Spartans; some of his works have an admiring pro–Spartan bias, especially the royal biography Agesilaus and the Constitution of the Spartans.
Xenophon's works span several genres and are written in plain-language Attic Greek, for which reason they serve as translation exercises for contemporary students of the Ancient Greek language. In the Lives and Opinions of Eminent Philosophers, Diogenes Laërtius observed that, as a writer, Xenophon of Athens was known as the “Attic Muse”, for the sweetness of his diction .