War between Megara and Corinth. - Megara and Pegae garrisoned by Athenians. - Review of Affairs at the Persian Court. - Accession of Artaxerxes. - Revolt of Egypt under Inarus. - Athenian Expedition to assist Inarus. - Aegina besieged. - The Corinthians defeated. - Spartan Conspiracy with the Athenian Oligarchy. - Battle of Tanagra. - Campaign and Successes of Myronides. - Plot of the Oligarchy against the Republic. - Recall of Cimon. - Long Walls completed. - Aegina reduced. - Expedition under Tolmides. - Ithome surrenders. - The Insurgents are settled at Naupactus. - Disastrous Termination of the Egyptian Expedition. - The Athenians march into Thessaly to restore Orestes the Tagus. - Campaign under Pericles. - Truce of five Years with the Peloponnesians. - Cimon sets sail for Cyprus. - Pretended Treaty of Peace with Persia. - Death of Cimon.
I. Cimon, summoned to the ostracism, was sentenced to its appointed term of banishment - ten years. By his removal, the situation of Pericles became suddenly more prominent and marked, and he mingled with greater confidence and boldness in public affairs. The vigour of the new administration was soon manifest. Megara had hitherto been faithful to the Lacedaemonian alliance - a dispute relative to the settlement of frontiers broke out between that state and Corinth. Although the Corinthian government, liberal and enlightened, was often opposed to the Spartan oligarchy, it was still essential to the interest of both those Peloponnesian states to maintain a firm general alliance, and to keep the Peloponnesian confederacy as a counterbalance to the restless ambition of the new head of the Ionian league. Sparta could not, therefore, have been slow in preferring the alliance of Corinth to that of Megara. On the other hand, Megara, now possessed of a democratic constitution, had long since abandoned the Dorian character and habits. The situation of its territories, the nature of its institutions, alike pointed to Athens as its legitimate ally. Thus, when the war broke out between Megara and Corinth, on the side of the latter appeared Sparta, while Megara naturally sought the assistance of Athens. The Athenian government eagerly availed itself of the occasion to increase the power which Athens was now rapidly extending over Greece. If we cast our eyes along the map of Greece, we shall perceive that the occupation of Megara proffered peculiar advantages. It became at once a strong and formidable fortress against any incursions from the Peloponnesus, while its seaports of Nisaea and Pegae opened new fields, both of ambition and of commerce, alike on the Saronic and the Gulf of Corinth. The Athenians seized willingly on the alliance thus offered to them, and the Megarians had the weakness to yield both Megara and Pegae to Athenian garrisons, while the Athenians fortified their position by long walls that united Megara with its harbour at Nisaea.
II. A new and more vast enterprise contributed towards the stability of the government by draining off its bolder spirits, and diverting the popular attention from domestic to foreign affairs.
It is necessary to pass before us, in brief review, the vicissitudes of the Persian court. In republican Greece, the history of the people marches side by side with the biography of great men. In despotic Persia, all history dies away in the dark recesses and sanguinary murthers of a palace governed by eunuchs and defended but by slaves.
In the year 465 B. C. the reign of the unfortunate Xerxes drew to its close. On his return to Susa, after the disastrous results of the Persian invasion, he had surrendered himself to the indolent luxury of a palace. An able and daring traitor, named Artabanus , but who seems to have been a different personage from that Artabanus whose sagacity had vainly sought to save the armies of Xerxes from the expedition to Greece, entered into a conspiracy against the feeble monarch. By the connivance of a eunuch, he penetrated at night the chamber of the king - and the gloomy destinies of Xerxes were consummated by assassination. Artabanus sought to throw the guilt upon Darius, the eldest son of the murdered king; and Artaxerxes, the younger brother, seems to have connived at a charge which might render himself the lawful heir to the throne. Darius accordingly perished by the same fate as his father. The extreme youth of Artaxerxes had induced Artabanus to believe that but a slender and insecure life now stood between himself and the throne; but the young prince was already master of the royal art of dissimulation: he watched his opportunity - and by a counter-revolution Artabanus was sacrificed to the manes of his victims. 
Thus Artaxerxes obtained the undisturbed possession of the Persian throne (B. C. 464). The new monarch appears to have derived from nature a stronger intellect than his father. But the abuses, so rapid and rank of growth in Eastern despotisms, which now ate away the strength of the Persian monarchy, were already, perhaps, past the possibility of reform. The enormous extent of the ill-regulated empire tempted the ambition of chiefs who might have plausibly hoped, that as the Persian masters had now degenerated to the effeminacy of the Assyrians they had supplanted, so the enterprise of a second Cyrus might be crowned by a similar success.