Titus Livius (Livy), The History of Rome, Book 7
D. Spillan, A.M., M.D., Ed.

14. The dictator, though he saw that a good result was brought about by a precedent not to be approved of, yet took on himself to do what the soldiers wished, an inquires of Tullius privately, what the nature of this transaction was, or on what precedent it was done? [2] Tullius earnestly entreated the dictator “not to believe him forgetful of military discipline, of himself, nor of the respect due to his general; that he had not declined to put himself at the head of the excited multitude, who generally were like to their instigators, lest any other person might step forward, such an excited multitude were wont to elect. [3] That for his own part he would do nothing without the orders of his general; that he also however must carefully see, that he keep the army in obedience. That minds so excited could not be put off: that they would choose for themselves time and place, if they were not granted by the general.” [4] While they are conversing in this way, it so happened, that as a Gaul was driving away some cattle feeding on the outside of the rampart two Roman soldiers took them from him. Stones were throw at them by the Gauls, then a shout was raised at the next Roman post, and several ran forward on both sides. [5] And now matters were not far from a regular engagement, had no the contest been quickly stopped by the centurions. By this event the testimony of Tullius was certainly confirmed with the dictator; and the matter not admitting of further delay, a proclamation is issued that they were to fight on the day following. [6] The dictator however, as one who went into the field relying more on the courage of his men than on their numerical strength, began to look about and consider how he might by some artifice strike terror into the enemy. With a sagacious mind he devises a new project, which many generals both of our own and of foreign countries have since adopted, some indeed in our own times. [7] He orders the panniers to be taken from the mules, and two side-cloths only being left, he mounts the muleteers on them, equipped with arms partly belonging to the prisoners, and some to the sick. [8] About a thousand of these being equipped, he mixes with them one hundred horsemen, and orders them to go up during the night into the mountains over the camp and to conceal [p. 464]themselves in the woods, and not to stir from thence, till they should receive a signal from him. [9] As soon as day dawned, he himself began to extend his line along the bottom of the mountain, for the express purpose that the enemy should face the mountains. [10] The measures for infusing groundless terror being now completed, which terror indeed proved almost more serviceable than real strength, the leaders of the Gauls first believed that the Romans would not come down to the plain: then when they saw them begin on a sudden to descend, they also, on their part eager for the fight, rush forward to the encounter; and the battle commenced before the signal could be given by the leaders.