Defeat and Flight of Darius. Hereupon the regiments on the right wing, perceiving that the Persians opposed to them had already been put to rout, wheeled round towards the Grecian mercenaries of Darius and their own hard-pressed detachment. Having driven the Greeks away from the river, they extended their phalanx beyond the Persian army on the side which had been broken; and attacking the Greeks on the flank, were already beginning to cut them up. However the Persian cavalry which had been posted opposite the Thessalians did not remain on the other side of the river during the struggle, but came through the water and made a vigorous attack upon the Thessalian squadrons.255 In this place a fierce cavalry battle ensued; for the Persians did not give way until they perceived that Darius had fled and the Grecian mercenaries had been cut up by the phalanx and severed from them. Then at last the flight of all the Persians was plainly visible. Their horses suffered much injury in the retreat, because the riders256 were heavily armed; and the horsemen themselves, being so many in number and retreating in panic terror without any regard to order along narrow roads, were trampled on and injured no less by each other than by the pursuing enemy. The Thessalians also followed them up with vigour, so that no fewer of the cavalry than of the infantry257 were slaughtered in the flight.
But as soon as the left wing of Darius was terrified and 102routed by Alexander, and the Persian king perceived that this part of his army was severed from the rest, without any further delay he began to flee in his chariot along with the first, just as he was.258 He was conveyed safely in the chariot as long as he met with level ground in his flight; but when he lighted upon ravines and other rough ground, he left the chariot there, divesting himself of his shield and Median mantle. He even left his bow in the chariot; and mounting a horse continued his flight. The night, which came on soon after, alone rescued him from being captured by Alexander;259 for as long as ............