After Googling Socrates and Plato, I found links to Xenophon, and decided to explore them, in doing so I found more references to the Delphic Oracle and the following;
Xenophon (In Greek Ξενοφῶν, c. 427-355 BC), son of Gryllus, of the deme Erchia of Athens, was a soldier, mercenary and an admirer of Socrates and is known for his writings on the history of his own times, the sayings of Socrates, and the life of Greece.
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 says 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." So the oracle told him which gods to pray and sacrifice to. When Xenophon returned to Athens and told Socrates of the oracle's advice, Socrates chastised him for putting the wrong question to the oracle, but said, "Since, however, you did so put the question, you should do what the god enjoined." (This, by the way, is the only personal interaction with Socrates that Xenophon relates to us in all his writings.)
In Cyrus' advance against the Persian king, he used many Greek mercenaries left unemployed by the cessation of the Peloponnesian War. Cyrus fought Artaxerxes at Cunaxa: the Greeks were victorious but Cyrus was killed, and shortly thereafter their general, Clearchus of Sparta, was invited to a peace conference, betrayed, and executed. The mercenaries, the Ten Thousand Greeks, found themselves deep in hostile territory, near the heart of Mesopotamia, far from the sea, and without leadership. 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 and then sailed westward and back to Greece. In Thrace, they helped Seuthes II make himself king. Xenophon's record of this expedition and the journey home was titled Anabasis ("The Expedition" or "The March Up Country" ).
Xenophon’s historical account in the Anabasis is one of the first written accounts of an analysis of the characters of a leader and an example of a type of leadership analysis that has come to be known as Great man theory. In the account, Xenophon described the character of the younger Cyrus, saying that “of all the Persians who lived after Cyrus the Great, he was the most like a king and the most deserving of an empire (p. 91).” Chapter six is recommended reading because it describes the characters of five defeated generals who were turned over to the enemy. Clearchus was quoted as believing that “a soldier ought to be more frightened of his own commander than of the enemy (p. 131).” Meno -- the eponymous character of Plato's dialogue -- was described as a man whose dominant ambition was to become wealthy (p. 133). Agias the Arcadian and Socrates the Achean were remembered for their courage and their consideration for friends (p. 135). (Reference: Xenophon. (published in Antiquity). The Persian Expedition. (Rex Warner, Trans.). With an introduction and notes by George Cawkwell. New York, NY: Penguin Books. First Penguin publication date of 1949.)
Xenophon was later exiled from Athens, probably because he fought under the Spartan king Agesilaus against Athens at Coroneia. (It is possible that he had already been exiled for his association with Cyrus, however.) The Spartans gave him property at Scillus, near Olympia in Elis, where the Anabasis was composed. His son Gryllus fought and died for Athens at the battle of Mantinea, while Xenophon was still alive, so Xenophon's banishment may have been revoked. Xenophon died at Corinth, or perhaps Athens, and his date of death is uncertain; it is known only that he survived his patron Agesilaus, for whom he wrote an encomium.
Diogenes Laertius says Xenophon was sometimes known as the "Attic Muse" for the sweetness of his diction; very few poets wrote in the Attic dialect. Xenophon is often cited as being the original "horse whisperer", having advocated sympathetic horsemanship in his On Horsemanship.