Titus Livius (Livy), The History of Rome, Book 43
William A. McDevitte, Sen. Class. Mod. Ex. Schol. A.B.T.C.D., Ed.

22. On that day Perseus encamped at the borders of the Aetolian territory; [2] and, on the next, arrived before Stratus, where, pitching his camp near the river Achelous, he expected that the Aetolians would come in crowds to put themselves under his protection; but on the contrary, he found the gates shut, and discovered that the very night on which he arrived, a Roman garrison, under Caius Popilius, lieutenant-general, had been received into the town. [3] The nobles, who, induced by the authority of Archidamus, while he was present, had invited the king, as soon as he went out to meet Perseus had become less zealous, and had given an opportunity to the opposite faction to call in Popilius, with one thousand foot, from Ambracia. [4] At the same juncture came also Dinarchus, general of the Aetolian cavalry, with six hundred foot and one hundred horse. It was well known that he came to Stratus intending to act with Perseus; but that, with the change of fortune, he had changed his mind, and joined the Romans, against whom he had come. [5] Nor was Popilius less on his guard than he ought to be among people of such fickle tempers. [6] He immediately took into his own keeping the keys of the gates, with the direction of the guard of the walls, and removed Dinarchus and the Aetolians, together with the young men of Stratus, into the citadel, under pretence of garrisoning it. [7] Perseus sounded the garrison, by addressing them from the eminences that hung [8??] over the upper part of the city, and finding that they were obstinate, and even kept him at a distance with weapons, removed his camp to the other side of the river Petitarus, about five miles from the town: there he held a council, wherein Archidamus and the refugees from Epirus were for detaining him there; [9] but the Macedonian nobles were of opinion that he ought not to fight against the severity of the season without having magazines of provisions; [10] in which case the besiegers would feel a scarcity sooner than the besieged, especially as the winter quarters of the enemy were at no great distance: being deterred by these considerations, he removed his camp into Aperantia. [11] The Aperantians, in consequence of the great interest and influence which Archidamus possessed among them, submitted to Perseus with universal consent; and Archidamus himself was appointed their governor, with a body of eight hundred soldiers.