Soon after the battle of Marathon a war broke out between Athens and AEgina. This war is of great importance in Grecian history, since to it the Athenians were indebted for their navy, which enabled them to save Greece at Salamis as they had already done at Marathon. AEgina was one of the chief maritime powers in Greece; and accordingly Themistocles urged the Athenians to build and equip a large and powerful fleet, without which it was impossible for them to humble their rival. There was at this time a large surplus in the public treasury, arising from the produce of the silver-mines at Laurium. It had been recently proposed to distribute this surplus among the Athenian citizens; but Themistocles persuaded them to sacrifice their private advantage to the public good, and to appropriate the money to building a fleet of 200 ships. The two leading citizens of Athens at this period were Themistocles and Aristides. These two eminent men formed a striking contrast to each other. Themistocles possessed abilities of the most extraordinary kind; but they were marred by a want of honesty. Aristides was inferior to Themistocles in ability, but was incomparably superior to him in honesty and integrity. His uprightness and justice were so universally acknowledged that he received the surname of the "Just." Themistocles was the leader of the democratical, and Aristides of the conservative party at Athens. After three or four years of bitter rivalry, the two chiefs appealed to the ostracism, and Aristides was banished (B.C. 483). We are told that an unlettered countryman gave his vote against Aristides at the ostracism, because he was tired of hearing him always called the Just. CHAPTER VIII. THE PERSIAN WARS.--THE BATTLES OF THERMOPYLAE, SALAMIS, AND PLATAEA, B.C. 480-479.