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.
Edition :
Plutarch Lives IX: Demetrius and Antony, Pyrrhus and Caius Marius, Ed. Jeffrey Henderson, trans. Bernadotte Perrin (The Loeb Classical Library 101), Harvard University Press: Cambridge/MA - London 1968 (first ed. 1920).
Remark :
date: The date is taken from the New Pauly. http://referenceworks.brillonline.com/entries/brill-s-new-pauly/pyrrhus-e1015710