Xenophon (ca. 431-354 BC), son of Gryllus, of the deme Erchia of Athens, was a soldier, mercenary and an admirer of Socrates. He took great care to preserve much of Socrates wisdom. Xenophon was exiled from Athens to Sparta, where he died after several years of Spartan patronage.
Xenophon is best remembered for his role as a mercenary in the employ of the Persian prince, Cyrus the Younger, on an expedition to depose Cyrus' brother, Artaxerxes II. The expedition was a disaster; their leaders were killed in short order, forcing the mercenaries, known as the Ten Thousand, to march through hostile territory to the Black Sea.
Xenophon was against Sokrates' decision to join Alkibiades' expedition to Sicily, claiming that the most vocal opponent, Kritias, spoke for most of the group. Sokrates deflected Xenophon by wondering how any man could speak for another.