You could try one of the novels based on Xenophon's Anabasis. The wikipedia entry on Xenophon says:
Xenophon's birth date is uncertain, but most scholars agree that he was born around 430 BC near the city of Athens, in the city-state of Attica which is known today as Modern Greece. Xenophon was born into the ranks of the upper classes, thus granting him access to certain privileges of the aristocracy of ancient Attica. While a young man, Xenophon participated in the expedition led by Cyrus the Younger against his older brother, the emperor Artaxerxes II of Persia, in 401 BC. Xenophon writes that he had asked the veteran Socrates for advice on whether to go with Cyrus, and that Socrates referred him to the divinely inspired Delphic oracle. Xenophon's query to the oracle, however, was not whether or not to accept Cyrus' invitation, but "to which of the gods he must pray and do sacrifice, so that he might best accomplish his intended journey and return in safety, with good fortune." The oracle answered his question and told him to which gods to pray and sacrifice. When Xenophon returned to Athens and told Socrates of the oracle's advice, Socrates chastised him.
Route of Xenophon and the Ten Thousand
Under the pretext of fighting Tissaphernes, Cyrus assembled a massive army composed of native Persian soldiers, but also a large number of Greeks, whom he viewed as superior fighters. Prior to waging war against the emperor, Cyrus proposed that the enemy was the Pisidians, and so the Greeks were unaware that they were to battle against the larger army of King Artaxerxes II. At Tarsus the soldiers became aware of Cyrus' plans to dispose of the king, and as a result refused to continue. Clearchus, however, convinced the Greeks to continue with the expedition. The army of Cyrus met the army of Artaxerxes II in the Battle of Cunaxa. Despite effective fighting by the Greeks, Cyrus was killed in the battle. Shortly thereafter, the Greek general Clearchus of Sparta was invited to a peace conference, where, alongside four other generals and many captains, he was betrayed and executed. The mercenaries, known as the Ten Thousand, found themselves without leadership far from the sea, deep in hostile territory near the heart of Mesopotamia. They elected new leaders, including Xenophon himself, and fought their way north through hostile Persians, Armenians, and Kurds to Trapezus on the coast of the Black Sea. They then made their way westward back to Greece. Once there, they helped Seuthes II make himself king of Thrace, before being recruited into the army of the Spartan general Thibron.
Xenophon's book Anabasis ("The Expedition" or "The March Up Country") is his record of the entire expedition against the Persians and the journey home. It is worth noting that the Anabasis was used as a field guide by Alexander the Great during the early phases of his expedition into Persia.
There are lots of choices. Some are historical (set in Ancient Greece). Two SF standouts are "March Upcountry" (and sequels) by Weber and Ringo and "Star Guard" by Andre Norton (which is the first of two novels in the Omnibus volume "Star Soldiers"). Both of these are available for free
(and DRM-free and multi-format) at the Baen Free Library
. Either look for the titles, or click on the 'authors' link.