Herodotus describes the decision to defend Thermopylæ as having been taken immediately after the return from Thessaly. Whether that was the case or not may be doubted. Herodotus himself, in another passage, seems to imply that an interval occurred, at any rate between the decision to defend Thermopylæ and the actual despatch of troops thither. He mentions again the decision, and then describes the despatch of troops from the Isthmus as having been made when the Greeks “heard that the Persian was in Pieria.” Xerxes was at Abydos when the expedition to Thessaly took place.[116] It is probable that not a little time was spent in discussing the plan of defence. It is, at any rate, quite plain from Herodotus’ account of Artemisium, that a very large section of the Greeks there present longed to seize upon any excuse for a retreat to the Isthmus. Was it, after all, considering their knowledge at the moment, so selfish a policy to fix the defence at a line in which they had some sort of confidence, rather than at one where the chances of success were impossible of calculation? The game they were playing must have seemed so desperate, that the Peloponnesians may well have conceived it a wiser policy to try, with some hope of success, to save a part of the land, than to attempt to save all, with a prospect of disastrous failure. Selfish consideration of their own special interests would naturally contribute to the formation of their views on the strategical question; but, at the same time, they had what must have seemed to them some very sound general arguments in support of those views. Herodotus shows quite clearly that there were times throughout the whole period of the war when the contest between the two policies was doubtful; times, too, when it seemed as if the Peloponnesian policy must win the day. That they were all but in equilibrium at the time of Artemisium, is evident. ◆Cf. H. vii. 206, _ad init._ and Diod. xi. 4.◆ The Northern policy had so far prevailed as to induce the Lacedæmonians to make a plausible effort for the defence of the Northern Greeks, who, if they thought themselves abandoned, would certainly refuse to join in the defence of the Isthmus, and remaining at home, would be forced to medize. #UNREALITY OF THE SPARTAN EFFORT.# On the other hand, some practical demonstration of the apparent hopelessness of defending Northern Greece, and of the apparent willingness of Sparta to make some sacrifice on their behalf, might conceivably induce them to aid in the defence of the Isthmus.