Titus Livius (Livy), The History of Rome, Book 9
D. Spillan, A.M., M.D., Cyrus Evans, Ed.

27. The accounts received of these matters, but more especially the hope of a revolt in Campania, for which a conspiracy had been formed, recalled the Samnites, who were turning towards Apulia, back to Caudium; [2] so that from thence, being near, they might, if any commotion should open them an opportunity, snatch Capua out of the hands of the Romans. [3] To the same place the consuls repaired with a powerful army. They both held back for some time, on the different sides of the defiles, the roads being dangerous to either party. [4] Then the Samnites, making a short circuit through an open tract, marched down their troops into level ground in the Campanian plains, and there the hostile camps first came within view of each other. [5] Trial of their strength in slight skirmishes was made on both sides, more frequently between the horse than the foot; and the Romans were no way dissatisfied either at the issue of these, or at the delay by which they protracted the war. [6] The Samnite generals, on the contrary, considered that their battalions were becoming weakened daily by small losses, and the general vigour abated by prolonging the war. [7] They therefore marched into the field, disposing their cavalry on both wings, with orders to give more heedful attention to the camp behind than to the battle; for that the line of infantry would be able to provide for their own safety. [8] The consuls took post, Sulpicius on the right wing, Pœtelius on the left. The right wing was stretched out wider than usual, where the [p. 598]Samnites also stood formed in thin ranks, either with design of turning the flank of the enemy, or to avoid being themselves surrounded. [9] On the left, besides that they were formed in more compact order, an addition was made to their strength, by a sudden act of the consul Pœtelius; for the subsidiary cohorts, which were usually reserved for the exigencies of a tedious fight, he brought up immediately to the front, and, in the first onset, pushed the enemy with the whole of his force. [10] The Samnite line of infantry giving way, their cavalry advanced to support them; and as they were charging in an oblique direction between the two lines, the Roman horse, coming up at full speed, disordered their battalions and ranks of infantry and cavalry, so as to oblige the whole line on that side to give ground. [11] The left wing had not only the presence of Pœtelius to animate them, but that of Sulpicius likewise; who, on the shout being first raised in that quarter, rode thither from his own division, which had not yet engaged. [12] When he saw victory no longer doubtful there, he returned to his own post with twelve hundred men, but found the state of things there very different; the Romans driven from their ground, and the victorious enemy pressing on them thus dismayed. [13] However, the arrival of the consul effected a speedy change in every particular; for, on the sight of their leader, the spirit of the soldiers was revived, and the bravery of the men who came with him rendered them more powerful aid than even their number; while the news of success in the other wing, which was heard, and after seen, restored the fight. [14] From this time, the Romans became victorious through the whole extent of the line, and the Samnites, giving up the contest, were slain or taken prisoners, except such as made their escape to Maleventum, the town which is now called Beneventum. It is recorded that thirty thousand of the Samnites were slain or taken.