Athens now became the acknowledged head and leader of the allied States, instead of Sparta, whose authority as a presiding State was now openly renunciated by the Athenians. The Panhellenic union under Sparta was now broken forever, and two rival States disputed the supremacy,—the maritime States adhering to Athens, and the land States, which furnished the larger part of the army at Platæa, adhering to Sparta. It was then that the confederacy of Delos was formed, under the presidency of Athens, which Aristides directed. His assessment was so just and equitable that no jealousies were excited, and the four hundred and sixty talents which were collected from the maritime States were kept at Delos for the common benefit of the league, managed by a board of Athenian officers. It was a common fear which led to this great contribution, for the Phœnician fleet might at any time reappear, and, co-operating with a Persian land force, destroy the liberties of Greece. Although Athens reaped the chief benefit of this league, it was essentially national. It was afterward indeed turned to aggrandize Athens, but, when it was originally made, was a means of common defense against a power as yet unconquered though repulsed. (M460) During all the time that the fortifications of Athens and the Peireus were being made, Themistocles was the ruling spirit at Athens, while Aristides commanded the fleet and organized the confederacy of Delos. It was thus several years before he became false to his Countrymen, and the change was only gradually wrought in his character, owing chiefly to his extravagant habits and the arrogance which so often attends success. (M461) During this period, a change was also made in the civil constitution of Athens. All citizens were rendered admissible to office. The State became still more democratic. The archons were withdrawn from military duties, and confined to civil functions. The stategi or generals gained greater power with the extending political relations, and upon them was placed the duty of superintending foreign affairs. Athens became more democratical and more military at the same time. (M462) From this time, 479 B.C., we date the commencement of the Athenian empire. It gradually was cemented by circumstances rather than a long-sighted and calculating ambition. At the head of the confederacy of Delos, opportunities were constantly presented of centralizing power, while its rapid increase of population and wealth favored the schemes which political leaders advanced for its aggrandizement. The first ten years of the Athenian hegemony or headship were years of active warfare against the Persians. The capture of Eion, on the Strymon, with its Persian garrison, by Cimonon, led to the settlement of Amphipolis by the Athenians; and the fall of the cities which the Persians had occupied in Thrace and in the various islands of the Ægean increased the power of Athens.