Xerxes was now advancing from Thermopylae, and Athens trembled for her existence, while the Peloponnesians were bent upon seeking shelter and safety in their peninsula, and upon fortifying themselves by a wall across the Corinthian isthmus. On the approach of the danger the Athenians had sent to Delphi to consult the oracle about the means they should employ for their safety, and the god had commanded Athens to defend herself behind wooden walls. This oracle, which probably had been given at the suggestion of Themistocles, was now also interpreted by him as referring to the fleet, and his advice to seek safety in the fleet was followed. He then further moved that the Athenians should abandon the city to the care of its tutelary deity, that the women, children, and infirm should be removed to Salamis, AEgina, or Troezen, and that the men should embark in the ships. The fleet of the Greeks, consisting of three hundred and eighty ships, assembled at Salamis, still under the supreme command of Eurybiades. When the Persians had made themselves masters of Attica, and Athens was seen in flames at a distance, some of the commanders of the fleet, under the influence of fear, began to make preparation for an immediate retreat. Themistocles saw the disastrous results of such a course, and exerted all his powers of persuasion to induce the commanders of the fleet to maintain their post; when all attempts proved ineffectual, Themistocles had recourse to threats, and thus induced Eurybiades to stay. The example of the admiral was followed by the other commanders also. In the meantime the Persian fleet arrived in the Saronic gulf, and the fears of the Peloponnesians were revived and doubled, and nothing seemed to be able to keep them together. At this last and critical moment Themistocles devised a plan to compel them to remain and face the enemy. He sent a message to the Persian admiral, informing him that the Greeks were on the point of dispersing, and that if the Persians would attack them while they were assembled, they would easily conquer them all at once, whereas it would be otherwise necessary to defeat them one after another. This apparently well-meant advice was eagerly taken up by the enemy, who now hastened, as he thought, to destroy the fleet of the Greeks. But the event proved the wisdom of Themistocles. The unwieldy armament of the Persians was unable to perform any movements in the narrow straits between the island of Salamis and the mainland. The Greeks gained a most complete and brilliant victory, for they only lost forty ships, while the enemy lost two hundred, or according to Ctesias, even five hundred. Very soon after the victory was decided, Xerxes with the remains of the fleet left the Attic coast and sailed toward the Hellespont. The battles of Artemisium and Salamis occurred in the same year, B.C. 480.