Xerxes willingly purchased the secret, and entrusted the task of outflanking the Greek position to the Immortals. They started at dusk and marched all night. The Phocian guards of the path seem to have neglected to place any outposts, and were not aware of the approach of the enemy till the crackling of the leaves under their feet, carried through the still air of night, gave them warning. They started up from their bivouack at the sound, and the Persians, surprised at the sight of an enemy whose presence they had not expected, halted. The Phocians seem not to have attempted to hold the path, but retreated to the crest of the hill and then made ready to defend themselves. The Persians left them alone, and continued their march. The Greeks at Thermopylæ had by this time received warning of what had happened. The soothsayer attached to the force is said to have read in the victims which he examined a prognostic of their fate. More definite information came from scouts who had been out on the hills, and who now came hurrying into the camp with the news. A council of war was hastily held. It could not agree, but the result was that the majority of the contingents retreated. Whether they did this with or without the orders of Leonidas is not certain. It is one of the matters about which it is almost impossible to arrive at the truth. Herodotus thinks that they were ordered to retire by Leonidas because he saw that they were unwilling to stay. This has a look of probability. As for Leonidas himself and his Spartans, they elected to stay. The inflexible military honour of their commonwealth forbade retreat. The seven hundred Thespians refused to depart, and must be allowed the glory of a still more heroic courage.[1] The Theban contingent was detained against its will. The soothsayer Megistias--his name ought to be preserved no less carefully than that of the traitor Ephialtes--refused to depart, though being not a Spartan, but an Acamanian by birth, he might have done so without discredit, but he sent away his only son. The name of the Thespian leader ought also to have its place on the roll of honour. It was Demophilus.