When the Parthians got to the town, which sat on a small hill, they encountered Roman legions confidently formed in battle order on the slopes. The Parthians rushed to attack - whether this order came from Pacorus or was a spontaneous charge is unknown. In any case, Ventidius ordered his troops, who had the advantage of high ground, to attack the horse-archers advancing up the slope. The horse-archers were forced into close-quartered combat against the legionaries and suffered heavily for it, for they were unsuited for such combat. The Parthian cavalry's will eventually broke and panic spread, many of the horse archers being driven down the slope where they crashed into their fellows in their desperation to escape. The horse-archers eventually fled or fell. Parthian heavy cavalry, which was stationed at the bottom of the hill, was enveloped and surrounded by the legionaries.