Titus Livius (Livy), The History of Rome, Book 7
Benjamin Oliver Foster, Ph.D., Ed.

14. Though the dictator felt that a good thing had been carried out in a way to set a bad example, yet he undertook to do as the soldiers wished. [2] In private he questioned Tullius what this proceeding meant and on what precedent he had acted. Tullius earnestly besought the dictator not to believe that he had forgotten the training of a soldier, nor forgotten himself and the honour due to his commander: the crowd, he said, had become excited; crowds were generally like their leaders, and he had not refused to lead it, for fear that some other might come forward, of the sort that an unruly mob was likely to choose; for his own part he would do nothing without the approval of his general. [3] But Sulpicius, he continued, must none the less be very wary himself, to keep the army in hand; postponement would not do, where feelings were so exasperated; the men would choose for themselves a time and place for fighting, if their general did not provide them. [4] While they were talking thus, [p. 403]it chanced that a Gaul attempted to drive off certain¹ sumpter animals that were grazing outside of the stockade, and two Roman soldiers took them away from him. These men were stoned by the Gauls. Whereupon a shout arose in the Roman outpost, and men ran forward on both sides. [5] And now the mellay was likely to end in a regular battle, had not the centurions speedily parted the combatants. Sulpicius was assured by this incident that Tullius spoke truth, and, the situation admitting of no delay, he announced a general engagement for the morrow.

Yet the dictator was entering a struggle in which he relied more on the spirit of his troops than on their strength. [6] He began therefore to cast about and every way to consider how he might strike terror into the enemy by some stratagem. His cleverness produced a new expedient, which many generals both of our own and foreign countries —some even in the present age —have since employed.² [7] Commanding the muleteers to remove the packsaddles from the mules, leaving only a pair of saddle-cloths on each, and arming them, partly with captured weapons, partly with those belonging to the sick, he mounted them. [8] Having in this way made out near a thousand, he mixed a hundred cavalrymen with them and ordered them to go up by night on to the mountains above the camp and conceal themselves in the woods, and not to stir from thence until they received a signal from him. [9] The dictator himself, as soon as it was light, began to deploy his front along the lower slopes, on purpose to make the enemy take their stand facing the mountains where the preparations had been made for inspiring them with a fear which, groundless [p. 405]though it was, yet served the Romans almost better³ than actual strength. [10] At first the Gallic leaders supposed that the Romans would not come down into the plain; then, when they saw that they had suddenly begun to descend, they also, being themselves eager for the combat, rushed into battle, and the fighting began before the signal could be given by the generals.