Titus Livius (Livy), The History of Rome, Book 31
Cyrus Evans, Ed.

42. Philip, when his troops had advanced almost to the rampart, ordered a retreat to be sounded, because both men and horses were fatigued, not so much by the action, as at once by the length of their march, and the extraordinary celerity with which they had made it. [2] He therefore despatched the horsemen by troops, and the companies of light infantry in turn, to procure water and take refreshment. [3] The rest he kept on guard, under arms, waiting for the main body of the infantry, which had marched with less expedition, on account of the weight of their armour. [4] As soon as these [p. 1385]arrived, they also were ordered to fix their standards, and, laying down their arms before them, to take food in haste; sending two, or at most three, out of each company, to provide water. In the mean time the cavalry and light infantry stood in order, and ready, in case the enemy should make any movement. [5] The Aetolians, as if resolved to defend their fortifications, (the multitude which had been scattered about the fields having, by this time, returned to the camp,) posted bodies of armed men at the gates, and on the rampart, and from this safe situation looked with a degree of confidence on the enemy, as long as they continued quiet. [6] But, as soon as the troops of the Macedonians began to move, and to advance to the rampart, in order of battle, and ready for an assault, they all quickly abandoned their posts, and fled through the opposite part of the camp, to the eminence where the Athamanians were stationed. During their flight in this confusion, many of the Aetolians were slain, and many made prisoners. [7] Philip doubted not that, had there been day-light enough remaining, he should have been able to make himself master of the camp of the Athamanians also; but the day having been spent in the fight, and in plundering the camp afterwards, he sat down under the eminence, in the adjacent plain, determined to attack the enemy at the first dawn of the following day. [8] But the Aetolians, under the same apprehensions which had made them desert their camp, dispersed, and fled during the following night. Amynander was of the greatest service; for, by his directions, the Athamanians, who were acquainted with the roads, conducted them into Aetolia, whilst the Macedonians pursued them over the highest mountains, through unknown paths. [9] In this disorderly flight, a few, missing their way, fell into the hands of the Macedonian horsemen, whom Philip, at the earliest dawn, on seeing the eminence abandoned, had sent to harass the marching body of the enemy.