Titus Livius (Livy), The History of Rome, Book 32
Cyrus Evans, Ed.

4. At this time, Philip was pushing on the siege of Thaumaci, with the utmost vigour, by means of mounds and engines, and was ready [2??] to bring up the ram to the walls, when he was obliged to relinquish the undertaking by the sudden arrival of the Aetolians, who, under the command of Archi- [p. 1398]damus, having made their way into the town between the posts of the Macedonians, never ceased, day or night, making continual sallies, sometimes against the guards, sometimes against the works of the besiegers. [3] They were at the same time favoured by the very nature of the place: for Thaumaci stands near the road from Thermopylae, and the Malian bay, as you go through Lamia, on a lofty eminence, hanging immediately over the narrow pass which the Thessalians call Caela.¹ [4] After passing through the craggy grounds of Thessaly, the roads are rendered intricate by the windings of the valleys, and on the near approach to the city, such an immense plain opens at once to view, like a vast sea, that the eye can scarcely reach the bounds of the expanse beneath. [5] From this surprising prospect it was called Thaumaci.² The city itself is secured, not only by the height of its situation, but by its standing on a rock, the stone of which had been cut away on all sides. [6] These difficulties, and the prize not appearing sufficient to recompense so much toil and danger, caused Philip to desist from the attempt. [7] The winter also was approaching; he therefore retired from thence, and led back his troops into winter quarters, in Macedonia.