=103.= The greatest citizen of Athens, after the death of Miltiades, was Aristides, called “the Just.” He was of noble birth and belonged to the Alcmæonid party, but he was ardently devoted to the interests of the people. Stern toward crime, whether in friends or foes, he was yet mild toward all persons; and so proverbial were his truth and impartiality, that when he held the office of archon the courts of law were deserted, all suitors preferring to submit their causes to his arbitration. =104.= His chief rival was Themis´tocles, a young man of great talents, and, perhaps, still greater ambition. At length his opposition rose to the pitch of proposing the ostracism, and Aristides was banished. It is said that, during the voting, the great archon was requested by a man who could not write, to inscribe the name of Aristides on an oyster-shell for him. “Has he ever injured you?” Aristides asked. “No,” said the man, “nor do I even know him by sight; but it vexes me to hear him always called the Just.” Aristides wrote his name on the shell, which was cast into the heap. As he left his native city he said, with his usual generosity, “May the Athenian people never know a day which shall force them to remember Aristides!” =105.= Themistocles was now without a rival in Athens. His acute mind perceived what his countrymen too willingly ignored, that the Persian invasions were only checked, not ended. Proud of the victory of Marathon, the Athenians believed that the Persians would never again dare to attack them. But Ægina was yet powerful, and a fierce enmity had long existed between the two states. Their merchants regarded each other as rivals in trade, while the free people of Athens hated the oligarchy of Ægina. Themistocles resolved to turn this enmity to account, in arming Athens against the greater though more distant danger. He persuaded the citizens to construct a fleet which should surpass that of Ægina, and to apply to that purpose the revenues from the silver mines of Laurium, near the extremity of the Attic peninsula. Two hundred triremes were built and equipped, and a decree was passed which required twenty to be added every year. Hitherto Attica had been more an agricultural than a maritime state; but Themistocles clearly saw that, with so small and sterile a territory, her only lasting power must be upon the sea. So strenuous were his exertions, that in the ten years that intervened between the first and the second Persian wars, the Athenians had trained a large number of seamen, organized their naval power, and were ready to be as victorious at Salamis as they had been at Marathon.