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

33. With the ensuing dawn the Carthaginians broke camp and the remainder of their army began to move. [2] The natives, on a signal being given, were already coming in from their fastnesses to occupy their customary post, when they suddenly perceived that some of their enemies were in possession of the heights and threatened them from above, and that others were marching through the pass. [3] Both facts presenting themselves at the same time to their eyes and minds kept them for a moment rooted to the spot. Then, when they saw the helter-skelter in the pass and the column becoming embarrassed by its own confusion, the horses especially being frightened [4??] and unmanageable, they thought that whatever they could add themselves to the consternation of the troops would be sufficient to destroy them, and rushed down from the cliffs on either side, over trails and trackless ground alike, with all the ease of habit. [5] Then indeed the Phoenicians had to contend at one and the same time against their foes and the difficulties of the ground, and the struggle amongst themselves, as each endeavoured to outstrip the rest in escaping from the danger, was greater than the struggle with the enemy. [6] The horses occasioned the greatest peril to the column. Terrified by the discordant yells, which the woods and ravines redoubled with their echoes, they quaked [p. 99]with fear; and if they happened to be hit or¹ wounded, were so maddened that they made enormous havoc not only of men but of every sort of baggage. [7] Indeed the crowding in the pass, which was steep and precipitous on both sides, caused many —some of them armed men —to be flung down to a great depth; but when beasts of burden with their packs went hurtling down, it was just like the crash of falling walls. [8] Dreadful as these sights were, still Hannibal halted for a little while and held back his men, so as not to augment the terror and confusion. [9] Then, when he saw that the column was being broken in two, and there was danger lest he might have got his army over to no avail, if it were stripped of its baggage, he charged down from the higher ground and routed the enemy by the very impetus of the attack, though he added to the disorder amongst his own troops. [10] But the flurry thus occasioned quickly subsided, as soon as the roads were cleared by the flight of the mountaineers; and the whole army was presently brought over the pass, not only without molestation but almost in silence. [11] Hannibal then seized a stronghold which was the chief place in that region, together with the outlying hamlets, and with the captured food and flocks supported his troops for three days. And in those three days, being hindered neither by the natives, who had been utterly cowed at the outset, nor very greatly by the nature of the country, he covered a good deal of ground.