Persian gold and her Greek allies.

Date Alliance
410 - 404 Persia supports Sparta to conclusion of Peloponnesian War.
404 - 399 Sparta retains fleet and the Delian League; march of 10,000; with Spartan complicity?
399 - 395 Sparta attacks Persia in Asia Minor; Persians withdraw subsidy from Sparta and support Athenian revival (Persians cover the cost of rebuilding of her walls); with Sparta threatened in the Peloponnesius, Agisilaos must withdraw from Asia Minor. Persian fleet manned with Greeks dominates the Aegean (Konon, a renegade Athenian)
395 - 386 Athenians lose Persian favor and gold by attacking Persian territories; Persia supports Sparta again
386 - 371 Persians support Sparta; Sparta breaks up alliances in Chalcidice and elswhere; sieze Thebes; Athenian fleet and new League tolerated, tho Athenians must relinquish any claim to Greek cities of Asia minor.