By thus doing he obtained a position which he could the better hold with his inferior forces, while the Romans, deeming that he intended to attack their camp on that side of the river, would be likely to move their whole army across and to give battle. This in fact Varro proceeded to do. Leaving ten thousand men in his own camp with orders to march out and attack that of Hannibal during the engagement, he led the rest of his troops over the river, and having united his force with that in the camp on the right bank, marched down the river until he faced the position which Hannibal had taken up.
This had been skillfully chosen. The river, whose general course was east and west, made a loop, and across this Hannibal had drawn up his army with both wings resting upon the river. Thus the Romans could not outflank him, and the effect of their vastly superior numbers in infantry would to some extent be neutralized. The following was the disposition of his troops.
The Spaniards and Gauls occupied the centre of the line of infantry. The Africans formed the two wings. On his left flank between the Africans and the river he placed his heavy African and Gaulish horse, eight thousand strong, while the two thousand Numidians were posted between the infantry and the river on the right flank. Hannibal commanded the centre of the army in person, Hanno the right wing, Hasdrubal the left wing; Maharbal commanded the cavalry.
Varro placed his infantry in close and heavy order, so as to reduce their front to that of the Carthaginians. The Roman cavalry, numbering two thousand four hundred men, was on his right wing, and was thus opposed to Hannibal’s heavy cavalry, eight thousand strong. The cavalry of the Italian allies, four thousand eight hundred strong, was on the left wing facing the Numidians.
Emilius commanded the Roman right, Varro the left. The Carthaginians faced north, so that the wind, which was blowing strongly from the south, swept clouds of dust over their heads full into the faces of the enemy. The battle was commenced by the light troops on both sides, who fought for some time obstinately and courageously, but without any advantage to either. While this contest was going on, Hannibal advanced his centre so as to form a salient angle projecting in front of his line. The whole of the Gauls and Spaniards took part in this movement, while the Africans remained stationary; at the same time he launched his heavy cavalry against the Roman horse.
The latter were instantly overthrown, and were driven from the field with great slaughter. Emilius himself was wounded, but managed to join the infantry. While the Carthaginian heavy horse were thus defeating the Roman cavalry, the Numidians maneuvered near the greatly superior cavalry of the Italian allies, and kept them occupied until the heavy horse, after destroying the Roman cavalry, swept round behind their infantry and fell upon the rear of the Italian horse, while the Numidians charged them fiercely in front.