Hannibal instructed Hasdrubal, the officer responsible for overseeing the army’s supply train amongst other things, to gather a great quantity of dry wood. These faggots were then tied to the horns of two-thousand plough oxen taken from the great herd of captured cattle. During the night, servants were ordered to light these torches and then drive the cattle up through the pass. With them went his experienced light infantrymen, who were tasked with keeping the herd together. In the meantime, the remainder of the army, who had earlier been given specific orders to eat and rest, formed up into a march column headed by the best of the close order infantry—most probably the Libyans. The Roman force in the pass, mistaking the fires for the main column, came down the slope to attack, but the confused skirmish was broken up when many of the panicking cattle stampeded through the middle. With the pass now open, the Carthaginian army was able to march through unopposed.

From Adrian Goldsworthy’s In the Name of Rome: The Men Who Won the Roman Empire, London: Phoenix, 2003, p. 42.