Battle of Arbela.—Flight of Darius. As soon as Darius began to set his whole phalanx in motion, Alexander ordered Aretes to attack those who were riding completely round his right wing; and up to that time he was himself leading his men in column. But when the Persians had made a break in the front line of their army, in consequence of the cavalry sallying forth to assist those who were surrounding the right wing, Alexander wheeled round towards the gap, and forming a wedge as it were of the Companion cavalry and of the part of the phalanx which was posted here, he led them with a quick charge and loud battle-cry straight towards Darius himself. For a short time there ensued a hand-to-hand fight; but when the Macedonian cavalry, commanded by Alexander himself, pressed on 167vigorously, thrusting themselves against the Persians and striking their faces with their spears, and when the Macedonian phalanx in dense array and bristling415 with long pikes had also made an attack upon them, all things at once appeared full of terror to Darius, who had already long been in a state of fear, so that he was the first to turn and flee.416 The Persians also who were riding round the wing were seized with alarm when Aretes made a vigorous attack upon them. In this quarter indeed the Persians took............