burned the city. The people fled to the Island of Salamis. All seemed lost. But on the 20th of September of the year 480 Themistocles forced the Persian fleet to give battle within the narrow straits which separated the Island of Salamis from the mainland and within a few hours he destroyed three quarters of the Persian ships.
THE PERSIANS BURN ATHENS
In this way the victory of Thermopylae came to naught. Xerxes was forced to retire. The next year, so he decreed, would bring a final decision. He took his troops to Thessaly and there he waited for spring.
But this time the Spartans understood the seriousness of the hour. They left the safe shelter of the wall which they had built across the isthmus of Corinth and under the leadership of Pausanias they marched against Mardonius the Persian general. The united Greeks (some one hundred thousand men from a dozen different cities) attacked the three hundred thou-
