alliance. Next year Pericles himself led an expedition in the Corinthian Gulf and secured the adhesion of Achaia.
But this was the end of Athenian successes. Cimon, after the battle of Tanagra, had been re- called, and now induced Athens to agree to a five years' truce with Sparta (B.C. 450), and once more to devote her energies to further measures against Persia; while at the same time a thirty years' peace was effected between Argos and Sparta, which practically put an end to the attempt to form a powerful counterpoise to Sparta in the Peloponnese. A year of successful war with the Persians at Cyprus followed (B.C. 449), in the course of which Cimon died, and an understanding was come to that the Persian fleets were not to sail into the Aegean, and that the king was to acknowledge the independence of all Hellenic towns. Whether this was secured by a formal treaty negotiated by Callias is not certain. But for the time it represents the practical state of affairs. Callias was a cousin of Aristides, and is generally referred to by later writers as having negotiated this peace. He at any rate seems to have been about this time on some mission to the Persian court. But that the king should have formally accepted such humiliating terms has been thought improbable.
Immediately afterwards, however, the Athenian supremacy on land, which the policy of Pericles had secured, began to melt away. In B.C. 448 a quarrel as to the management of the temple and Oracle at Delphi produced another outbreak of hostilities
