XI. Although the banishment of Cimon had appeared to complete the triumph of the popular party in Athens, his opinions were not banished also. Athens, like all free states, was ever agitated by the feud of parties, at once its danger and its strength. Parties in Athens were, however, utterly unlike many of those that rent the peace of the Italian republics; nor are they rightly understood in the vague declamations of Barthelemi or Mitford; they were not only parties of names and men - they were also parties of principles - the parties of restriction and of advance. And thus the triumph of either was invariably followed by the triumph of the principle it espoused. Nobler than the bloody contests of mere faction, we do not see in Athens the long and sweeping proscriptions, the atrocious massacres that attended the party-strifes of ancient Rome or of modern Italy. The ostracism, or the fine, of some obnoxious and eminent partisans, usually contented the wrath of the victorious politicians. And in the advance of a cause the people found the main vent for their passions. I trust, however, that I shall not be accused of prejudice when I state as a fact, that the popular party in Athens seems to have been much more moderate and less unprincipled even in its excesses than its antagonists. We never see it, like the Pisistratidae, leagued with the Persian, nor with Isagoras, betraying Athens to the Spartan. What the oligarchic faction did when triumphant, we see hereafter in the establishment of the Thirty Tyrants. And compared with their offences, the ostracism of Aristides, or the fine and banishment of Cimon, lose all their colours of wrong.
XII. The discontented advocates for an oligarchy, who had intrigued with Nicomedes, had been foiled in their object, partly by the conduct of Cimon in disavowing all connexion with them, partly by the retreat of Nicomedes himself. Still their spirit was too fierce to suffer them to forego their schemes without a struggle, and after the battle of Tanagra they broke out into open conspiracy against the republic.
The details of this treason are lost to us; it is one of the darkest passages of Athenian history. From scattered and solitary references we can learn, however, that for a time it threatened the democracy with ruin. 
The victory of the Spartans at Tanagra gave strength to the Spartan party in Athens; it also inspired with fear many of the people; it was evidently desirable rather to effect a peace with Sparta than to hazard a war. Who so likely to effect that peace as the banished Cimon? Now was the time to press for his recall. Either at this period, or shortly afterward, Ephialtes, his most vehement enemy, was barbarously murdered - according to Aristotle, a victim to the hatred of the nobles.
XIII. Pericles had always conducted his opposition to Cimon with great dexterity and art; and indeed the aristocratic leaders of contending parties are rarely so hostile to each other as their subordinate followers suppose. In the present strife for the recall of his rival, amid all the intrigues and conspiracies, the open violence and the secret machination, which threatened not only the duration of the government, but the very existence of the republic, Pericles met the danger by proposing himself the repeal of Cimon's sentence.
Plutarch, with a childish sentimentality common to him when he means to be singularly effective, bursts into an exclamation upon the generosity of this step, and the candour and moderation of those times, when resentments could be so easily laid aside. But the profound and passionless mind of Pericles was above all the weakness of a melodramatic generosity. And it cannot be doubted that this measure was a compromise between the government and the more moderate and virtuous of the aristocratic party. Perhaps it was the most advantageous compromise Pericles was enabled to effect; for by concession with respect to individuals, we can often prevent concession as to things. The recall  of the great leader of the anti-popular faction may have been deemed equivalent to the surrender of many popular rights. And had we a deeper insight into the intrigues of that day and the details of the oligarchic conspiracy, I suspect we should find that, by recalling Cimon, Pericles saved the constitution. 
XIV. The first and most popular benefit anticipated from the recall of the son of Miltiades in a reconciliation between Sparta and Athens, was not immediately realized further than by an armistice of four months. 
About this time the long walls of the Piraeus were completed (B. C. 455), and shortly afterward Aegina yielded to the arms of the Athenians (B. C. 455), upon terms which subjected the citizens of that gallant and adventurous isle (whose achievements and commerce seem no less a miracle than the greatness of Athens when we survey the limits of their narrow and rocky domain) to the rival they had long so fearlessly, nor fruitlessly braved. The Aeginetans surrendered their shipping, demolished their walls, and consented to the payment of an annual tribute. And so was fulfilled the proverbial command of Pericles, that Aegina ought not to remain the eyesore of Athens.
XV. Aegina reduced, the Athenian fleet of fifty galleys, manned by four thousand men , under the command of Tolmides, circumnavigated the Peloponnesus - the armistice of four months had expired - and, landing in Laconia, Tolmides burnt Gythium, a dock of the Lacedaemonians; took Chalcis, a town belonging to Corinth, and, debarking at Sicyon, engaged and defeated the Sicyonians. Thence proceeding to Cephallenia, he mastered the cities of that isle; and descending at Naupactus, on the Corinthian gulf, wrested it from the Ozolian Locrians.