Xenophon of Athens (; Ancient Greek: Ξενοφῶν; c. 430 – 355/354 BC) was a Greek military leader, philosopher, and historian. At the age of 30, he was elected as one of the leaders of the retreating Greek mercenaries, the Ten Thousand, who had been part of Cyrus the Younger's attempt to seize control of the Achaemenid Empire. As the military historian Theodore Ayrault Dodge wrote, "the centuries since have devised nothing to surpass the genius of this warrior".
For at least two millennia, it has been debated whether Xenophon was first and foremost a general, historian, or philosopher. For the majority of time in the past two millennia, Xenophon was recognized as a philosopher. Quintilian in The Orator's Education discusses the most prominent historians, orators and philosophers as examples of eloquence and recognizes Xenophon's historical work, but ultimately places Xenophon next to Plato as a philosopher. Today, Xenophon is recognized as one of the greatest writers of antiquity. Xenophon's works span multiple genres and are written in plain Attic Greek, which is why they have often been used in translation exercises for contemporary students of the Ancient Greek language. In the Lives and Opinions of Eminent Philosophers, Diogenes Laërtius observed that Xenophon was known as the "Attic Muse" because of the sweetness of his diction.