Titus Livius (Livy), The History of Rome, Book 43
Alfred C. Schlesinger, Ph.D., Ed.

22. On that day camp was pitched at the edge of Aetolian territory; thence on the second day they arrived at Stratus. [2] Although, when he pitched camp there near the Inachus River, Perseus expected the Aetolians to come streaming out of every gate to put themselves under his protection, he found that the gates were closed and that on the very night when he had arrived a Roman garrison, under the staff-officer Gaius Popilius, had been received. [3] The leading men, driven by the influence of Archidamus while he was there, had summoned the king, but had become less active when Archidamus had gone out to meet Perseus, and had given an opportunity to the opposing party of summoning Popilius with a thousand infantry from Ambracia.¹ [4] Just in time, too, came Dinarchus, the chief of cavalry² of the Aetolian League, with six hundred infantry and a hundred cavalry. It was well known that he had come to Stratus as if on his way to Perseus, but then, changing his mind with his [5??] luck, had joined the Romans, against whom he had come. Popilius, for his part, was not more off his guard than he should have been, considering the fickle temperaments which encompassed him. [6] He at once took control of the keys of the gates and the guarding of the walls, and removed to the citadel, ostensibly as [7??] its garrison, Dinarchus and his Aetolians, along with the young men of Stratus. [8] Perseus, after attempting parleys from the hills which overhang the upper part of the [p. 81]city,³ on seeing that they were determined and were⁴ even keeping him at a distance with missiles, pitched his camp five miles from the city across the river Petitarus. [9] There he called a council and, although Archidamus and the Epirote deserters tried to keep him where he was, when the leading Macedonians were of the opinion that he should not fight against the unfavourable season of the year without having arranged for supplies, since the [10??] blockaders were bound to feel the want of them before the blockaded, especially when winter-quarters of the enemy were not far distant, Perseus in fear moved his camp into Aperantia.⁵ [11] The Aperantians, because of their great regard for Archidamus and his influence with that people, by general agreement received Perseus; Archidamus himself, with a garrison of eight hundred men, was put in charge of the city.