Xenophon: - Xenophon was a Greek historian, soldier, and philosopher born in Athens around 430 BC. He was a student of Socrates and fought as a mercenary in various conflicts throughout his life. In 401 BC, Xenophon joined the expedition of Cyrus the Younger, a Persian prince who sought to overthrow his brother, the king of Persia. After Cyrus was killed in battle, Xenophon led a group of Greek soldiers known as the Ten Thousand on a dangerous retreat across enemy territory, an event he later wrote about in his famous work, the "Anabasis". Xenophon also wrote several other works, including the "Hellenica", which covers the events in Greece from 411 BC to 362 BC, and the "Cyropaedia", a fictionalized biography of Cyrus the Great. In addition to his military and historical pursuits, Xenophon was also interested in philosophy and wrote several works on ethics, including "Memorabilia", a collection of Socratic dialogues. He believed in the importance of piety, obedience to the law, and the virtues of the Greek city-state system. Xenophon spent his later years in the Greek city of Corinth, where he continued to write and engage in philosophical discussions. He died around 354 BC at an advanced age.