But the great king never carried out his plan of again attacking Greece, for he died in 485 B.C., after having reigned for thirty-six years. His son Xerxes succeeded to the throne of Persia. CHAPTER XLIII ARISTIDES IS OSTRACISED Four years after the battle of Marathon, Themistocles and Aristides were the two chief citizens in Athens. Themistocles wished to make Athens a great sea-power, for he was sure that some day the Persians would return. He believed that if the Athenians were able to destroy the Persian fleet, all would be well. The land forces of the enemy would be powerless to conquer Greece. But if Athens was to have a better fleet, Themistocles knew that she must first have a better harbour. The one that the Athenians used was at Phalerum, where the sea almost reached the city. It was only an open roadstead, a place where ships might ride at anchor, which would be of little use to protect vessels from an enemy. Themistocles knew a better site than Phalerum, where a strong harbour might be built. This was the rocky peninsula of Piraeus, which was about four miles from Athens. By his advice three harbours were made here, into which the largest vessels could enter. Yet the opening to all three was such that it could be closed easily with chains and logs, so as to prevent the entrance of an enemy. The Piraeus soon grew into a large town, for those who did not own land flocked to the port in the hope of finding work. Not only did Themistocles persuade the Athenians to fortify the Piraeus, but he also made Athens a great sea-power. At this time there was money to spare in the public treasury, for a rich bed of silver had been discovered in an old mine. This money was to be divided among the Athenians. Themistocles was brave enough to risk the anger of the people by proposing that it should not be given to them, but should be used to build ships. The Athenians were eager to conquer the people of Ægina who for years had harried their coasts, and they agreed to his proposal more readily than Themistocles had dared to hope. With the money the State built two hundred ships, so the people were able to conquer their enemy and were well content. But it was Themistocles alone who wished to prepare Greece for a great Persian invasion. Of this the Athenians had no fear. When the ships were ready, Themistocles saw that the soldiers must be trained to manage the vessels, to become indeed good sailors. A wise Greek named Plato tells us that Themistocles ‘from steady soldiers turned the Greeks into mariners and seamen, tossed about the sea, and gave occasion for the reproach against him, that he took away from the Athenians the spear and the shield, and bound them to the bench and the oar.’ Aristides and Themistocles were rivals. They were brought up together, and when they were boys they usually took different sides, just as they continued to do when they were men.