Titus Livius (Livy), The History of Rome, Book 35
Cyrus Evans, Ed.

29. At break of day, the Cretan light infantry and the Tarentine horse began an engagement on the bank of the rivulet. Telemnastus, a Cretan, commanded his countrymen; Lycortas of Megalopolis, the cavalry. [2] The enemies' watering party also was guarded by Cretan auxiliaries and Tarentine horsemen. The fight was, for a considerable time, doubtful, as the troops on both sides were of the same kind, and armed alike; [3] but as the contest advanced, the tyrant's auxiliaries gained an advantage, both by their superiority of numbers, and because Philopœmen had given directions to his officers, that, after maintaining the contest for a short time, they should betake themselves to flight, and draw the enemy on to the place of the ambuscade. The latter, pursuing the runaways, in disorderly haste, through the valley, were most of them wounded and slain, before they discovered their concealed foe. [4] The targeteers had posted themselves in such order, as far as the breadth of the valley allowed, that they easily gave a passage to their flying friends, through openings in their ranks; [5] then starting up themselves, hale, fresh, and in regular order, they briskly attacked the enemy, whose ranks were broken, who were scattered in confusion, and were, besides, exhausted with fatigue and wounds. [6] The victory was no longer doubtful; the tyrant's troops instantly turned their backs, and flying with much more precipitation than they had pursued, were driven into their camp. [7] Great numbers were killed and taken in the pursuit; and the consternation would have spread through the camp also, had not Philopœmen ordered a retreat to be sounded; for he dreaded the ground (which was rough and dangerous to advance on without caution) more than he did the enemy. [8] Judging, both from the issue of the battle and from the disposition of the enemy's leader, in what apprehension he then was, he sent to him one of the auxiliary soldiers in the character of a deserter, to assure him positively, that the Achaeans had resolved [9??] to advance, next day, to the river Eurotas, which runs almost close to the walls, in order to intercept his way, so that the tyrant could have no retreat to the city when he required it, and to prevent any provisions being brought thence to the [p. 1583]camp; [10] and that they intended, at the same time, to try whether any could be prevailed on to desert his cause. Although the deserter did not gain entire credit, yet he afforded to one, who was full of apprehensions, a plausible pretext for leaving his camp. [11] On the day following, he ordered Pythagoras, with the auxiliaries and cavalry, to mount guard before the rampart; [12] and then, marching out himself with the main body of the army, as if intending to offer battle, he ordered them to return with all haste to the city.