The Persian cavalry and transport filtered slowly through the narrow passage of Thermopylæ, and marched on towards Athens, while a series of naval encounters went on at sea. The Hellenic fleet retreated before the advance of the Persian shipping, which suffered seriously through its comparative ignorance of the intricate coasts and of the tricks of the local weather. Weight of numbers carried the Persian army forward to Athens; now that Thermopylæ was lost, there was no line of defence nearer than the Isthmus of Corinth, and this meant the abandonment of all the intervening territory, including Athens. The population had either to fly or submit to the Persians. Thebes with all Bœotia submitted, and was pressed into the Persian army, except one town, Platæa, whose inhabitants fled to Athens. The turn of Athens came next, and great efforts were made to persuade her to make terms; but, instead, the whole population determined to abandon everything and take to the shipping. The women and non-combatants were carried to Salamis and various adjacent islands. Only a few people too old to move and a few dissentients remained in the town, which was occupied by the Persians and burnt. The sacred objects, statues, etc., which were burnt at this time, were afterwards buried in the Acropolis by the returning Athenians, and have been dug up in our own day with the marks of burning visible upon them. Xerxes sent off a mounted messenger to Susa with the news, and he invited the sons of Peisistratus, whom he had brought back with him, to enter upon their inheritance and sacrifice after the Athenian manner upon the Acropolis. Meanwhile, the Hellenic confederate fleet had come round to Salamis, and in the council of war there were bitter differences of opinion. Corinth and the states behind the Isthmus wanted the fleet to fall back to that position, abandoning the cities of Megara and Ægina. Themistocles insisted with all his force on fighting in the narrows of Salamis. The majority was steadily in favour of retreat, when there suddenly arrived the news that retreat was cut off. The Persians had sailed round Salamis and held the sea on the other side. This news was brought by that Aristides the Just, of whose ostracism we have already told; his sanity and eloquence did much to help Themistocles to hearten the hesitating commanders. These two men had formerly been bitter antagonists; but with a generosity rare in those days, they forgot their differences before the common danger. At dawn the Greek ships pulled out to battle.