Titus Livius (Livy), The History of Rome, Book 40
Evan T. Sage, Ph.D. and Alfred C. Schlesinger, Ph.D., Ed.

48. From there he next led his troops to the town of Alce, where the camp of the Celtiberians lay from which the ambassadors had recently come. [2] When he had harried them with skirmishes for some time, sending his light troops against their outposts, he was daily engaging in battle on a larger scale, that he might draw them all outside their defences. [3] When he saw that what he was seeking had been sufficiently achieved, he ordered the commanders of the auxiliaries that, letting the conflict flag as if they were overcome by superior numbers, they should suddenly turn their backs and flee headlong to the camp; he himself formed his troops inside the rampart at all the gates. [4] No long time passed when, as agreed, he saw the column of his own fugitives and behind them, pursuing in loose order, the barbarians. [5] He had formed his line within the rampart for just this purpose. And so, waiting only long enough to allow his troops to escape into the camp through an [p. 153]open entrance, raising a shout he burst out from all the¹ gates at once. The enemy did not withstand the unexpected attack. [6] Those who had come to capture the camp could not even defend their own: for at once they were repulsed and routed, presently driven in terror within the rampart, and finally stripped of their camp. [7] That day nine thousand of the enemy were killed; three hundred and twenty were taken alive, and a hundred and twelve horses and thirty-seven military standards were captured. Of the Roman army one hundred and nine fell.