Titus Livius (Livy), The History of Rome, Book 39
Evan T. Sage, Ph.D., Ed.

31. When the Spaniards saw the two Roman columns on the nearer bank, in order to catch them before they could unite and form their ranks, rushing hastily out of their camp they hastened to the conflict. [2] There was a fierce fight at the outset, the Spaniards on the one side being puffed up by their recent victory, the Roman soldiers on the other incensed by their unaccustomed defeat. [3] The fiercest fight was in the centre of the line, composed of the two bravest [p. 315]legions. When the enemy saw that they could be¹ dislodged in no other way, they began to attack in wedge formation; and ever more men, more closely massed, were pressing on the centre. [4] After Calpurnius the praetor saw that the line was in distress there, he sent Titus Quinctilius Varus and Lucius Juventius Talna, the lieutenants, at full speed to encourage the single legions; [5] he ordered them to instruct and remind the troops that in them lay all their hopes of victory and of holding Spain: if they retired from that spot, no one in that army would ever see —not to mention Italy —even the farther bank of the Tagus river. [6] He himself with the cavalry of the two legions, making a short detour, took in flank the wedge of the enemy which was pressing on the centre. [7] Quinctius with the allied cavalry attacked the other flank of the enemy. But the cavalry of Calpurnius fought far more furiously, and the praetor beyond the rest: [8] for he was both the first to strike down an enemy and so threw himself into the midst that it could scarcely be told to which side he belonged; and the cavalry were inspired by the remarkable valour of the praetor and in turn inspired the infantry. [9] Shame moved the senior centurions when they saw the praetor amid the weapons of the enemy. And so each for himself urged on the standard-bearers, ordered them to advance and the soldiers to follow at once. [10] The shouting was renewed by all: an attack was launched as if from higher ground. And so they swept forward like a torrent and overwhelmed the panic-stricken enemy, nor as they charged wave after wave could they be resisted. [11] The cavalry pursued the fugitives to the camp, and mingling with the throng of the enemy [p. 317]made their way inside the rampart; there the battle² was renewed by the troops who had been left to guard the camp, and the Roman cavalry were forced to dismount. [12] While they were fighting thus the fifth legion came up; then, as they could, new forces were joining the battle. Spaniards were being slaughtered everywhere through the whole camp, and not more than four thousand men escaped. [13] About three thousand of them, who had kept their weapons, occupied a mountain near by; a thousand, most of them partially armed, straggled through the fields. There had been more than thirty-five thousand of the enemy, of whom so small a remnant survived the battle. One hundred and thirty-three standards were taken. [14] Of the Romans and allies a few more than six hundred fell, and of the auxiliaries from the province about a hundred and fifty. [15] The loss of five tribunes of the soldiers and of a few Roman knights particularly gave the appearance of a bloody victory.³ [16] They remained in the camp of the enemy because there had been no opportunity to fortify their own. [17] Before an assembly the next day Gaius Calpurnius praised and decorated the cavalry with trappings for their horses and proclaimed publicly that the enemy had been defeated and his camp taken and captured mainly through their efforts. Quinctius, the other praetor, decorated his cavalry with chains and clasps. [18] Also many centurions from both armies were honoured, especially those who had held the centre of the line.