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. The pass through Trachis into Hellas 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. To the west 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. It was the Phocians who built it for fear of the Thessalians when these came from Thesprotia to dwell in the Aeolian land, the region which they now possess. Since the Thessalians were trying to subdue them, the Phocians made this their protection, and in their search for every means to keep the Thessalians from invading their country, they then turned the stream from the hot springs into the pass, so that it might be a watercourse. The ancient wall had been built long ago and most of it lay in ruins; those who built it up again thought that they would in this way bar the foreigner's way into Hellas. Very near the road is a village called Alpeni, and it is from here that the Greeks expected to obtain provisions.