Titus Livius (Livy), The History of Rome, Book 21
Benjamin Oliver Foster, Ph.D., Ed.

5. For the rest, from the day on which he was proclaimed commander-in-chief, as though Italy had been assigned to him for his field of operations and he [2??] had been instructed to make war on Rome, he felt that no postponement was permissible, lest he too, like his father Hamilcar, and afterwards Hasdrubal, should be overtaken, while delaying, by some accident, and resolved upon attacking the Saguntines.¹ [3] But since an attack on them must certainly provoke the Romans to hostile action, he marched first into the territory of the Olcades —a tribe living south of the Ebro, within the limits of the Carthaginians but not under their dominion —that he might appear not to have aimed at the Saguntines but to have been drawn into that war by a chain of events, as he conquered the neighbouring nations and annexed their territories. [4] Cartala,² a wealthy town, the capital of that tribe, he stormed and sacked; and this so terrified the lesser towns that they submitted and agreed to an indemnity. The victorious army, enriched with spoil, was led back to New Carthage for [5] the winter. There, by a generous partition of the booty and the faithful discharge of all arrears of pay, he confirmed them all, both citizens and allies, in their allegiance to himself; and early in the spring pushed forward into the land of [6] the Vaccaei. Their cities, Hermandica³ and [p. 15]Arbocala, were taken by assault. Arbocala, thanks to the⁴ bravery and numbers of its inhabitants, held out for a [7] long time. The fugitives from Hermandica, uniting with the exiles of the [8] Olcades —the tribe which had been subdued in the previous summer —roused up the Carpetani, and falling upon Hannibal as he was returning from the Vaccaei, not far from the river Tagus, threw his column, encumbered as it was with booty, into [9] some disorder. Hannibal refrained from battle and encamped on the bank of the river. As soon as the enemy were settled for the night and silent, he crossed the river by a ford, and so laid out his rampart as to allow them room for crossing, resolving to attack them as they were [10] passing over. He ordered his cavalry to charge their column of foot when they saw that it had [11??] entered the stream, and posted the elephants, of which he had forty, along the bank. The Carpetani, together with the contingents of the Olcades and Vaccaei, numbered a hundred thousand —an invincible array, had they been going to fight in a [12] fair field. And so, inspired by a native intrepidity, confiding in their multitude, and believing —since they supposed that their enemies had retreated out of fear —that victory was delayed but till they should have passed the river, they broke into a cheer, and, staying for no man's orders, rushed into the stream wherever it happened to [13] be nearest. From the other side a great body of cavalry was sent in [14] against them. The meeting in mid-channel was no equal conflict, for there the footmen were unsteady, and, scarce trusting to the ford, might even have been overthrown by unarmed riders, urging their horses forward at haphazard; while the horsemen, having [p. 17]their bodies and weapons free and horses that were⁵ steady even in the deep pools, could fight either at close quarters or [15] long range. A great part of them perished in the stream; some the eddying current carried over to their enemies, where they were trampled down by [16] the elephants. The rearmost, who could retreat to their own bank more safely, were gathering from the various directions in which they had fled, when, before they could recover from so great a panic, Hannibal entered the stream in a fighting column, and driving them in confusion from the bank, laid waste their fields, and in a few days' time received the surrender of the [17] Carpetani also. And now everything south of the Ebro, except Saguntum, was in the hands of the Carthaginians.