Titus Livius (Livy), The History of Rome, Book 22
Benjamin Oliver Foster, Ph.D., Ed.

45. While they wasted time, rather quarrelling than consulting, Hannibal withdrew the rest of his troops, whom he had kept in line till far on in the day, [2??] into his camp, and sent the Numidians across the river to attack the men from the smaller Roman camp who were fetching water. [3] They had hardly come out upon the other bank when their shouts and tumult sent that unorganized rabble flying, and they rode on till they came to the party that was stationed in front of the rampart, and almost to the very gates. [4] So wholly outrageous, however, did it seem that by now even a Roman camp should be terrorized by irregular auxiliaries, that only one thing kept the Romans from crossing the river forthwith and giving battle —the fact that Paulus happened then to be in command.

[5] The next morning, therefore, Varro, whom the lot had made commander for that day, hung out the signal, without saying a word of the matter to his colleague, and, making his troops fall in, led them over the river. Paulus followed him, for he could more easily disapprove the plan than deprive it of his help. [6] Once across, they joined to their own the [p. 351]forces which they had kept in the smaller camp,¹ and marshalled their battle-line as follows: on the right wing —the one nearer the river —they placed the Roman cavalry, and next them the Roman foot; [7] the left wing had on the outside the cavalry of the allies; and nearer the centre, in contact with the Roman legions, the infantry of the allies. The slingers and other light-armed auxiliaries were formed up in front. [8] The consuls had charge of the wings, Terentius of the left, Aemilius of the right; and Geminus Servilius was entrusted with the centre.