Plutarch Pyrrhus 25

[1] But the power of the Samnites had been shattered, and their spirits were broken, in consequence of many defeats at the hands of the Romans. They also cherished considerable resentment against Pyrrhus because of his expedition to Sicily; hence not many of them came to join him. Pyrrhus, however, divided his army in to two parts, sent one of them into Lucania to attack the other consul, that he might not come to the help of his colleague,

[2] and led the other part himself against Manius Curius, who was safely encamped near the city of Beneventum and was awaiting assistance from Lucania; in part also it was because his soothsayers had dissuaded him with unfavourable omens and sacrifices that he kept quiet. Pyrrhus, accordingly, hastening to attack this consul before the other one came up, took his best men and his most warlike elephants and set out by night against his camp.

[3] But since he took a long circuit through a densely wooded country, his lights did not hold out, and his soldiers lost their way and straggled. This caused delay, so that the night passed, and at daybreak he was in full view of the enemy as he advanced upon them from the heights, and caused much tumult and agitation among them.
  Manius, however, since the sacrifices were propitious and the crisis forced action upon him, led his forces out and attacked the foremost of the enemy, and after routing these, put their whole army to flight, so that many of them fell and some of their elephants were left behind and captured.

[4] This victory brought Manius down into the plain to give battle; here, after an engagement in the open, he routed the enemy at some points, but at one was overwhelmed by the elephants and driven back upon his camp, where he was obliged to call upon the guards, who were standing on the parapets in great numbers, all in arms, and full of fresh vigour.

[5] Down they came from their strong places, and hurling their javelins at the elephants compelled them to wheel about and run back through the ranks of their own men, thus causing disorder and confusion there. This gave the victory to the Romans, and at the same time the advantage also in the struggle for supremacy. For having acquired high courage and power and a reputation for invincibility from their valour in these struggles, they at once got control of Italy, and soon afterwards of Sicily.