Titus Livius (Livy), The History of Rome, Book 31
Evan T. Sage, Ph.D. Professor of Latin and Head of the Department of Classics in the University of Pittsburgh, Ed.

35. The king, fearing the gamble of a decisive battle at this early moment, sent four hundred Tralles —a people of Illyria, as I have elsewhere¹ said —and three hundred Cretans, adding to the infantry an equal number of cavalry under command of Athenagoras, one of his nobles, to harass the Roman cavalry. [2] The Romans, on the other hand —their battle-line was a little more than half a mile away —sent out skirmishers and about two squadrons of cavalry, that the infantry and cavalry might equal the enemy in number also. [3] The king's forces assumed that the type of fighting would be that to which they were accustomed, that the cavalry, alternately advancing and retreating, would now discharge their weapons and now retire, that the swift movements of the Illyrians would be useful for sallies and sudden [p. 105]charges, and that the Cretans would shower arrows² upon the enemy advancing in disorder. [4] The Roman attack, no more vigorous than stubborn, prevented the carrying out of this plan; [5] for just as if they were in regular line of battle, both the skirmishers, after hurling their spears, came to a hand-to-hand combat with their swords, and the cavalry, as soon as they had charged the enemy, stopping their horses either fought from horseback or leaped from their saddles and fought mingled with the footmen. [6] So neither the king's cavalry, unused to a stationary battle, could stand against the Romans, nor his infantry, running to and fro and almost unprotected by armour, against the light-armed Romans, equipped with shield and sword and prepared alike for defence or offence. [7] So they did not sustain the struggle, but relying on nothing else than their swiftness of foot they fled to the camp.