Xenophon

Xenophon was a Greek author, a contemporary of Plato, and, like him, a student of Socrates. Xenophon's writings ranged from philosophic works to his treatise on estate management, entitled Oikonomia (that is, Economics); but his most famous written work was Anabasis. Xenophon, as a gentleman adventurer and aspiring historian, accompanied a force of Greek mercenaries in the service of Cyrus in a Persian war of succession. The mercenaries marched deep into the Persian empire and were victorious -- but both Cyrus and their own general were killed. For the march back to Greece, the mercenaries had to elect a new general -- and they elected Xenophon. He led them to Greek territory and later wrote it all up in Anabasis.

There must be a cast-of-thousands movie in the story, but, so far as I know, it has never been shot.