The Thirty Years' Truce, though concluded upon terms seemingly disadvantageous to Athens, afforded an interval of repose highly favourable to her prosperity, only interrupted by one successful effort. It was during this period that Pericles was enabled to carry out his views into action, with the amplest means that the state could furnish at his command, and with scarcely a breath of opposition to divert him from his purpose. The history of Athens during the continuance of the Thirty Years' Truce may be properly comprised in a general survey of his administration.

Pericles, to describe his policy in a few words, had two objects mainly in view throughout his public life: to extend and strengthen the Athenian empire, and to raise the confidence and self-esteem of the Athenians themselves to a level with the lofty position which they occupied. Almost all his measures may clearly be referred to one or the other of these ends. There are only a few as to which it may seem doubtful whether they can be traced to any higher aim than that of establishing his own power, and whether they must not be regarded as a sacrifice by which, at the expence of his principles, he purchased that popularity which was the indispensable condition of success in all his undertakings.

The condition of the greater part of the states which composed the Athenian confederacy had, as we have seen, undergone a great change in the time of Cimon, and through his management.