Hannibalic War (2.5-2.6)

After a brief pause he attacked Taurasia, a Gallic town, took it by storm, and put the prisoners to death, in order to strike terror into the rest of the Gauls. Then he advanced to the river Eridanus, now called the Padus [Po], where the Romans were at war with the Gallic tribe called the Boii, and pitched his camp. The Roman consul, Publius Cornelius Scipio, was at that time contending with the Carthaginians in Spain. When he learned of Hannibal's incursion into Italy, he left his brother, Gnæus Cornelius Scipio, in charge of affairs in Spain and sailed for Etruria. Marching thence with such allies as he could collect, he came before Hannibal to the Po. He sent Manlius and Atilius, who were conducting the war against the Boii, back to Rome, as they had no right to command when a consul was on the ground, and taking their forces drew them up for battle with Hannibal. After a skirmish and a cavalry engagement, the Romans were surrounded by the Africans and fled to their camp. The next night they took refuge in Placentia, a place strongly fortified, crossing the Po and then breaking down the bridge. Nevertheless Hannibal made a new bridge and crossed the river.

These exploits, one after another, following his passage of the Alps, exalted Hannibal's fame among the Cisalpine Gauls as an invincible commander and one most highly favored by fortune. In order to increase the admiration of those barbarians, who were easily deceived, he frequently changed his clothes and his hair, using carefully prepared devices each time. When the Gauls saw him moving among their people now an old man, then a young man, and again a middle-aged man, and continually changing from one to the other, they were astonished and thought that he partook of the divine nature. Sempronius, the other consul, being then in Sicily and learning what had happened, embarked his forces, came to Scipio's aid, and encamped at a distance of forty stades from him. The following day they all made ready for battle. The river Trebia separated the hostile armies, which the Romans crossed before daylight on a raw, sleety morning of the spring equinox, wading in the water up to their breasts. Hannibal allowed his army to rest till the second hour and then marched out.