Titus Livius (Livy), The History of Rome, Book 9
Benjamin Oliver Foster, Ph.D., Ed.

27. The rumour of these events, and still more the hope of a Campanian insurrection, which had been the aim of the conspirators, recalled the Samnites from Apulia, on which their attention had been fixed, to Caudium; [2] in the hope that, being there so near, they might, if any disturbance should afford the opportunity, seize Capua from the Romans; and to Caudium came the consuls, with a powerful force. [3] both armies at first held back, each on its own side of the pass, for either would have been at a disadvantage in advancing against the other. [4] then the Samnites made a short detour over open ground, and brought their army down to the plain, where the hostile forces were, for the first time, encamped in sight of one another. some skirmishing followed, in which both sides made trial more often of their cavalry than their foot. [5] The Romans were not dissatisfied either with the outcome of these brushes or with the delays by which the campaign was protracted. [6] to the Samnite leaders, on the contrary, it appeared that [p. 269]their forces were daily diminishing with petty¹ losses, and were wasting away with the prolongation of the war.

[7] they accordingly made ready for a general engagement, dividing their cavalry between the wings, with orders to pay more attention to the camp, to prevent any attack upon it, than to the battle; for the infantry would sufficiently safeguard the line. [8] of the consuls, Sulpicius took up his post on the right wing, Poetelius on the left. The formation on the right was spread out over a considerable distance, and on that wing the Samnites, too, were drawn up in ranks of little depth, either meaning to tum the Romans' flank, or to keep their own from being turned. [9] The troops on the left, besides being drawn up in closer order, had received an accession to their strength from a plan conceived on the spur of the moment by Poetelius. [10] for those subsidiary cohorts which were wont to be kept fresh in reserve, to meet the chance needs of a long engagement, he sent immediately into the fighting line; and by using all his strength at once, he forced the enemy back at the first assault. as the Samnite infantry wavered, their cavalry moved up to support them. but while they came obliquely onward, in the interval between the armies, the Roman cavalry charged them at the gallop, confounding the ranks and the formations of horse and foot, until they had routed the entire army at that point.² [11] on that wing Sulpicius was present, as well as Poetelius, to animate the soldiers, for when the shouting arose upon the left, he had ridden over there, leaving his own men, who were not yet come to grips with [p. 271]the enemy. [12] but perceiving his colleague's victory³ to be safe, he left him and rode off with twelve hundred men to his own wing. [13] there he found affairs in a different posture; the Romans had been driven out of their position, and the victorious enemy were charging their disordered ranks. but all was quickly changed by the arrival of the consul. for the sight of their general revived the spirits of the soldiers, and the brave men who followed him were a greater succour than their numbers indicated; and the tidings of their comrades' victory, which they soon saw for themselves, restored the battle. [14] presently the Romans had begun to conquer all along the line, while the Samnites, giving up the struggle, were massacred or made prisoners, except those who fled to Maleventum, the city which is now called Beneventum.⁴ tradition avers that some thirty thousand Samnites were slain or captured.