Titus Livius (Livy), The History of Rome, Book 40
William A. McDevitte, Sen. Class. Mod. Ex. Schol. A.B.T.C.D., Ed.

39. In the same year Fulvius Flaccus, the proconsul in Spain, as his successor did not come to the province at the usual time, having drawn out the troops from their winter quarters, proceeded to lay waste the farther part of Celtiberia, whose inhabitants had not come in to make submission. [2] But by this proceeding he rather provoked than terrified the spirits of the barbarians; so that, having collected secretly a body of forces, they beset the Manlian pass, through which [p. 1896]they knew, with certainty, that the Roman army would march. [3] Gracchus had commissioned his colleague, Lucius Postumius Albinus, who was going to the Farther Spain, to desire Quintus Fulvius to bring his forces to Tarraco, where he intended to discharge the veterans, to distribute the reinforcements among the respective corps, and reorganize the entire army. [4] The day also was mentioned to Flaccus, and that not very distant, on which his successor would arrive. [5] When tidings of this new arrangement had compelled Flaccus to drop the business which he had undertaken, and to lead away the troops in haste out of Celtiberia, the barbarians, unacquainted with the reason, and supposing that he had discovered their revolt and secret assembling of an army, and that he was retreating through fear, beset the pass with the greater determination. When the Roman army entered this defile, at the dawn of day, immediately the enemy starting up attacked it at two sides at once. [6] And when Flaccus saw this, he put down the confusion arising among [7??] the soldiers by giving orders through the centurions that every man should keep his post, in the order of march, and make ready his arms; [8] then collecting the baggage and beasts of burden, into one spot, partly by himself, partly by the help of the lieutenants-general, and military tribunes, he formed his troops as the time and place required, without any confusion. [9] He put them in mind, that they were to engage with men “who had been twice reduced to submission; that guilt and perfidy, not valour or courage, were their only accessions. That these people had put it in their power to make their return to their country which otherwise would have been ignoble, glorious and splendid; for they would now carry home their swords red from the slaughter, and spoils dropping blood.” [10] The time did not allow more to be said, as the enemy were rapidly advancing upon them; the extremities of the wings were already engaged, and quickly after the entire lines.