 His cavalry and Gallic infantry were concealed in the hills in the depth of the wooded valley from which the Romans would first enter, so that they could quickly sally out and close the entrance, blocking the Roman route of retreat.Then he posted his light troops at intervals along the heights overlooking the plain, with orders to keep well hidden in the woods until signalled to attack.Also, the night before the battle commenced, Hannibal ordered his men to light campfires on the hills of Tuoro, at a considerable distance, so as to convince the Romans that his forces were further away than they actually were.