Plutarch Pyrrhus 17

[1] This taught Pyrrhus to be more on his guard; and seeing that his cavalry were giving way, he called up his phalanx and put it in array, while he himself, after giving his cloak and armour to one of his companions, Megacles, and hiding himself after a fashion behind his men, charged with them upon the Romans. But they received and engaged him, and for a long time the issue of the battle remained undecided; it is said that there were seven turns of fortune, as each side either fled back or pursued.

[2] And indeed the exchange of armour which the king had made, although it was opportune for the safety of his person, came near overthrowing his cause and losing him the victory. For many of the enemy assailed Megacles, and the foremost of them, Dexoüs by name, smote him and laid him low, and then, snatching away his helmet and cloak, rode up to Laevinus, displaying them, and shouting as he did so that he had killed Pyrrhus.

[3] Accordingly, as the spoils were carried along the ranks and displayed, there was joy and shouting among the Romans, and among the Greeks consternation and dejection, until Pyrrhus, learning what was the matter, rode along his line with his face bare, stretching out his hand to the combatants and giving them to know him by his voice. At last, when the Romans were more than ever crowded back by the elephants, and their horses, before they got near the animals, were terrified and ran away with their riders, Pyrrhus brought his Thessalian cavalry upon them while they were in confusion and routed them with great slaughter.

[4]
  Dionysius states that nearly fifteen thousand of the Romans fell, but Hieronymus says only seven thousand; on the side of Pyrrhus, thirteen thousand fell, according to Dionysius, but according to Hieronymus less than four thousand. These, however, were his best troops; and besides, Pyrrhus lost the friends and generals whom he always used and trusted most.

[5] However, he took the camp of the Romans after they had abandoned it, and won over to his side some of their allied cities; he also wasted much territory, and advanced until he was within three hundred furlongs’ distance from Rome. And now, after the battle, there came to him many of the Lucanians and Samnites. These he censured for being late, but it was clear that he was pleased and proud because with his own troops and the Tarantines alone he had conquered the great force of the Romans.