The year 371 bc, when the Thebans crushed the Spartan army at Leuctra, was a turning point for all of Greece as well as for Thebes and the Boeotian Confederacy. Until that time Sparta, no matter how Isocrates and other Athenians might have wished otherwise, was the generally recognized leader of Greece, a position first acknowledged in deed as early as the Persian War. The Peloponnesian War and the Spartan victory over Athens underscored Sparta's position of leadership. By the instrument of surrender in 404 Athens itself became a subject-ally of Sparta, and in the words of Xenophon, the Athenians were required “to count the same people friends and enemies as the Lacedaemonians did and to follow them both by land and sea wherever they should lead the way.” Although challenged by a formidable coalition of Greek states in the Corinthian War, Sparta emerged triumphant, largely owing to Persian support.

The entry of Persia into the political and diplomatic affairs of Greece was a complicated factor of enormous significance. After the King's Peace of 386, leadership in Greece, though still the purview of Sparta, was intimately connected to the favor and policies of the Persian Empire. The precise nature of that connection is disputed. G. L. Cawkwell has argued that the King formally recognized Sparta as the prostatēs of the Peace, while D. M. Lewis has disputed his conclusion. On the basis of present knowledge, the dispute is perhaps insoluble, simply because the sources remain uniformly silent on the point.