7.173.3
They remained there for only a few days, for messengers came from Alexander son of Amyntas, the Macedonian. These, pointing out the size of the army and the great number of ships, advised them to depart and not remain there to be trodden under foot by the invading host. When they had received this advice from the messengers (as they thought their advice was sound and that the Macedonian meant well by them), the Greeks followed their counsel.
7.173.4
To my thinking, however, what persuaded them was fear, since they had found out that there was another pass leading into Thessaly by the hill country of Macedonia through the country of the Perrhaebi, near the town of Gonnus; this was indeed the way by which Xerxes' army descended on Thessaly. The Greeks accordingly went down to their ships and made their way back to the Isthmus.
ch. 174
7.174.1
This was the course of their expedition into Thessaly, while the king was planning to cross into Europe from Asia and was already at Abydos. The Thessalians, now bereft of their allies, sided with the Persian wholeheartedly and unequivocally. As a result of this they, in their acts, proved themselves to be most useful to the king.
ch. 175
7.175.1
When they had come to the Isthmus, the Greeks, taking into account what was said by Alexander, deliberated as a body how and where they should stand to fight. It was decided that they should guard the pass of Thermopylae, for they saw that it was narrower than the pass into Thessaly and nearer home.
7.175.2
The pass, then, which brought about the fall of those Greeks who fell at Thermopylae, was unknown to them until they came to Thermopylae and learned of it from the men of Trachis. This pass they were resolved to guard and so stay the barbarian's passage into Hellas, while their fleet should sail to Artemisium in the territory of Histiaea. These places are near to each other, and each force could therefore be informed of the other's doings. As for the places themselves, their nature is as follows.
ch. 176
7.176.1
Artemisium is where the wide Thracian sea contracts until the passage between the island of Sciathus and the mainland of Magnesia is but narrow. This strait leads next to Artemisium, which is a beach on the coast of Euboea, on which stands a temple of Artemis.
7.176.2
The pass through Trachis into Hellas note is fifty feet wide at its narrowest point. It is not here, however, but elsewhere that the way is narrowest, namely, in front of Thermopylae and behind it; at Alpeni, which lies behind, it is only the breadth of a cart-way, and it is the same at the Phoenix stream, near the town of Anthele.
7.176.3
To the west note of Thermopylae rises a high mountain, inaccessible and precipitous, a spur of Oeta; to the east of the road there is nothing but marshes and sea. In this pass are warm springs for bathing, called the Basins by the people of the country, and an altar of Heracles stands nearby. Across this entry a wall had been built, and formerly there was a gate in it.
