Titus Livius (Livy), The History of Rome, Book 25
D. Spillan, A.M., M.D., Cyrus Evans, Ed.

21. The Roman legions, and the praetor, Fulvius, were in the neighbourhood of Herdonia, where, receiving intelligence of the approach of the enemy, they had nearly torn up the standards and gone out to battle without the praetor's orders; nor did any thing tend more to prevent it than the assured hope they entertained that they could do so whenever they pleased, consulting only their own will. [2] The following night, Hannibal having obtained information that the camp was in a state of tumult, and that most of the troops were in a [3??] disorderly manner urging the general to give the signal, and calling out to arms, and therefore feeling convinced that an opportunity presented itself for a successful battle, distributed three thousand light troops in the houses in the neighbourhood, and among the thorns and woods. [4] These, on a signal being given, were to rise up from their lurking-place with one accord; and Mago, with about two thousand horse, was ordered to occupy all the roads in the direction in which he supposed their flight would be directed. [5] Having made these preparations during the night, he led his troops into the field at break of day. Nor did Fulvius decline the challenge; not so much from any hope of success entertained by himself, as drawn by the blind impetuosity of his soldiers. [6] Accordingly, the line itself was formed with the same want of caution with which they entered the field, agreeably to the whim of the soldiers, who came up as chance directed, and took their stations just where they pleased; which they afterwards abandoned, as fear or caprice suggested. [7] The first legion and the left wing of the allied troops were drawn up in front. The line was extended to a great length, the tribunes remonstrating, that there was no strength in it, and that wherever the enemy made the charge they would break through it: but no salutary advice reached their minds, nor even their ears. [8] Hannibal was now come up, a general of a totally different character, with an army neither similar in its nature, nor similarly marshalled. The consequence was, that the Romans did not so much as sustain their shout and first attack. [9] Their general, equal to Centenius in folly and temerity, but by no means to be compared with him in courage, when he saw [p. 988]things going against him, and his troops in confusion, hastily mounting his horse, fled from the field with about two hundred horsemen. [10] The rest of the troops, beaten in front, and surrounded on the flank and rear, were slaughtered to such a degree, that out of eighteen thousand men, not more than two thousand escaped. The enemy got possession of the camp.