Titus Livius (Livy), The History of Rome, Book 28
Frank Gardener Moore, Professor Emeritus in Columbia University, Ed.

2. He was some three miles away when not one of the enemy had yet noticed them; a rugged terrain and brush-covered hills kept them concealed. [2] There in a deep valley that was consequently unseen he bade his soldiers sit down and take food. Meantime came the scouts confirming the deserters' reports. [3] Then the Romans piled their light baggage in the centre, took up their arms and advanced to fight in regular line of battle. They were a mile away when they were seen by the enemy, who suddenly began to show alarm. Mago too, leaving his [p. 7]camp at the first shouting and uproar, rode up at a¹ gallop. In the army of the Celtiberians there were four thousand men with long shields and two hundred horsemen. [4] This complete legion —and they were the best of his troops —was placed in the front line. The rest, the light-armed, he posted as reserves. [5] While he was leading the men in that order out of their camp and they had scarcely got beyond the rampart, the Romans hurled their javelins at them. [6] The Spaniards squatted down to meet the enemy's volley; then they in turn rose to hurl their weapons. After the Romans in dense array, as usual, had received these on their shields held close together, men fought at close quarters and began to use swords. [7] But the roughness of the ground made nimbleness of no use to the Celtiberians, whose custom it is to be skirmishers in battle, and at the same time it was not unfavourable for the Romans, accustomed to a static order of battle, except that restricted spaces and intervening thickets broke up their ranks, and they [8??] were forced to engage now singly, now in couples, as though with men paired against them. Whatever hampered the flight of the enemy exposed them to slaughter, as if they were fettered. [9] And now that nearly all the Celtiberian heavy infantry had been slain, the [10??] light-armed and the Carthaginians who had come to their aid from the other camp were being routed and cut down. Not more than two thousand infantry and all the cavalry escaped with Mago almost at the beginning of the battle. [11] Hanno, the second in command, was captured alive with those who had been the last to arrive when the battle was nearly over. Almost all the cavalry and such old soldiers as there were in the infantry [p. 9]followed Mago in flight and on the tenth day reached² Hasdrubal³ in the region of Gades. [12] The newly recruited Celtiberians slipped away into the neighbouring forests and thence scattered to their homes.

[13] This very timely victory had made a sudden end, not so much indeed of the war already in progress, as of the resources for some subsequent war, had it been possible for the Carthaginians, after calling out the Celtiberian nation, to entice other tribes also to take up arms. [14] Accordingly Scipio praised Silanus in generous terms and cherished the hope of ending the war if only he should not retard the fulfilment by his own delaying. Aiming to finish what remained of the war he proceeded into the farthest part of Spain against Hasdrubal. The Carthaginian, in order to ensure the loyalty of his allies, had his camp at that time, as it happened, in Baetica.⁴ [15] Nevertheless he suddenly took up his standards and with the appearance of a flight rather than of a march led his men all the way to the Ocean and Gades. [16] But before taking ship along the strait to Gades, thinking he would be the object of attack so long as he kept his army together, he scattered his entire force among the cities in every direction, that they might defend themselves by walls and at the same time defend walled cities by their arms.