=143.= Athens, under the lead of Pericles, now entered upon the most brilliant period of her history. A dispute between Megara and Corinth involved Athens on the former and Sparta on the latter side, and thus led to the First Peloponnesian War (B. C. 460-457). At the same time, a more distant enterprise tempted the Athenians. Egypt had now cast off the last semblance of obedience to Persia, and hailed a deliverer and sovereign in the person of Inarus. In looking about him for allies, Inarus naturally sought the aid of those who, at Marathon, had first broken the power of the Persians. The Athenians engaged gladly in the war, and sent a fleet of two hundred triremes to the Nile. The events of the campaign have been recorded in the History of Persia.[48] [Sidenote: B. C. 457.] =144.= The war in Greece went on with great vigor. The Athenians were defeated at Halæ, but soon after won a naval battle at Cec´ryphali´a,[49] which more than retrieved their reputation. Ægina now joined in the war, and the Athenians landed upon the island and besieged the city. A Peloponnesian army came to the aid of Ægina, while the Corinthians seized the opportunity to invade Megaris. With all her forces employed either in Egypt or Ægina, they hoped that Athens would be overcome by this new attack. But Myron´ides mustered an army of boys and old men exempt from service, and marched at once to the assistance of Megara. In the battle which ensued, neither party acknowledged itself defeated, but the Corinthians withdrew to their capital, while the Athenians held the field and erected a trophy. Unable to bear the reproaches of their government, the Corinthian army returned after twelve days and raised a monument upon the field, claiming that the victory had been theirs. But the Athenians now attacked them anew, and inflicted a decisive and disgraceful defeat. =145.= In the midst of these enterprises abroad, great public works were going on in Athens. Cimon had already planned a line of fortifications to unite the city with its ports, and the spoils of the Persians, taken at the Eurymedon and at Cyprus, had been assigned for the expense. Under the direction of Pericles, the building began in earnest. One wall was extended to Phalerum, and another to Piræus; but as it was found difficult to defend so large an inclosed space, a second wall to Piræus was added, at a distance of 550 feet from the first. Between these Long Walls a continuous line of dwellings bordered the carriage-road, nearly five miles in length, which extended from Athens to its principal harbor.