Xenophon

Xenophon (c. 430 – 354 BC), also known as Xenophon of Athens, was a Greek historian, soldier, mercenary, philosopher and a contemporary and admirer of Socrates. He is known for his writings on the history of his own times, the 4th century BC. He preserved the sayings of Socrates, and descriptions of life in ancient Greece and the Persian Empire. 
His most famous book was the "Anabasis", about the escape of Greek mercenaries after they fought for Cyrus the Younger, a pretender to the throne of Persia.