Titus Livius (Livy), The History of Rome, Book 27
Cyrus Evans, Ed.

2. Marcellus, who was not much discouraged at this so great a disaster, sent a letter to the senate at Rome, with an account of the loss of the general and army at Herdonea; [2] observing, however, “that he who, after the battle of Cannae, had humbled Hannibal when elated with victory, was now marching against him, and that he would cause that his present joy and exultation should not continue long.” [3] At Rome, indeed, the grief occasioned by what had occurred, and the fears entertained for the future, were excessive. [4] The consul passing out of Samnium into Lucania, pitched his camp at Numistro, on a plain within view of Hannibal, who occupied a hill. [5] He added also another demonstration of his confidence; for he was the first to lead out his troops to battle, nor did Hannibal decline fighting when he saw the standards carried out from the gates. However, they drew up their forces so that the right wing of the Carthaginians was extended up the hill, while the left wing of the Romans was contiguous to the town. [6] For a long time neither side had any advantage; but the battle having continued from the third hour till night, and the first lines, which consisted, on the part of the Romans, of the first legion and the right wing of the allied infantry, on the part [7??] of Hannibal, of the Spanish soldiers, the balearic slingers, and the elephants, which were driven into the field after the commencement of the battle, being fatigued with fighting, the first legion was relieved by the third, and the right wing of allied infantry by the left; [8] while on the part of the enemy fresh troops took up the battle in place of those who were tired. [9] A new and desperate conflict suddenly arose, instead of that which was so feebly maintained, their minds and bodies being unimpaired by fatigue; but night separated the combatants while the victory was undecided. The following day the Romans stood drawn up for battle from sunrise till [p. 1092]late in the day; but none of the enemy coming out against them, they gathered the spoils at their leisure, and collecting the bodies of their own troops into a heap, burnt them. [10] The following night Hannibal decamped in silence, and moved off into Apulia. As soon as daylight discovered the flight of the enemy, Marcellus, leaving his wounded under the protection of a small garrison at Numistro, in command of which he placed Lucius Furius Purpureo, a military tribune, commenced a close pursuit of Hannibal, and overtook him at Venusia. [11] Here, during several days, parties of troops sallying from the outposts, battles took place between foot and horse promiscuously, rather irregular than important, but which for the most part were favourable to the Romans. [12] The armies were marched thence through Apulia without any engagement worth recording; for Hannibal marched by night, seeking an opportunity for ambuscade, but Marcellus never followed him except in broad daylight, and after having explored the country.