Leontius saw that there were two circumstances which would lead to Philip's attainment of his purpose and render the Aetolians incapable of facing the situation, first the rapidity and unexpectedness of the Macedonian advance
and secondly the fact that the Aetolians, never dreaming that Philip would so readily venture to throw himself into the country round Thermus owing to its great natural strength, would be caught off their guard and absolutely unprepared for such an occurrence.
In view of this, then, and still pursuing his purpose, he recommended Philip to encamp near the Achelous and give his troops a longer rest after their night march, his object being to give the Aetolians a brief time at least to organize their resistance.
Aratus, however, seeing that the time for the enterprise was now or never and that Leontius was evidently hampering it, implore Philip not to let the opportunity slip by delaying his advance.
The king, displeased as he already was with Leontius, took this advice continued his march.
Crossing the Achelous he advanced briskly on Thermus plundering and devastating the country as he went,
leaving as he proceeded Stratus, <a class="linkToPlace" target="_blank" href="/place?placename=Agrinium&groupId=305&placeId=598">Agrinium</a>, and Thestia on his left and <a class="linkToPlace" target="_blank" href="/place?placename=Conope&groupId=489&placeId=919">Conope</a>, <a class="linkToPlace" target="_blank" href="/place?placename=Lysimachia&groupId=719&placeId=1319">Lysimachia</a>, Trichonium, and Phytaeum on his right.
Reaching a town called <a class="linkToPlace" target="_blank" href="/place?placename=Metapa&groupId=762&placeId=1382">Metapa</a>, situated on Lake Trichonis and close to the neighbouring pass, at a distance of about six miles from Thermus,
he occupied this place, which the Aetolians had abandoned, with a force of five hundred men serving to cover his entrance into the pass and secure his retreat:
for all this bank of the lake is steep, rugged and wooded to the water's edge, so that the path along it is quite narrow and very difficult.
After this, putting his mercenaries at the head of the column, the Illyrians behind them, and last of all the peltasts and heavy-armed soldiers, he advanced through the pass, with the Cretans guarding his rear and the Thracians and light-armed troops advancing parallel to him through the country on his right flank, his left flank being protected by the lake for a distance of about thirty stades.
Walbank Commentary