After they were gone from him with this answer, he laid himself down in his tent and slept the rest of the night more soundly than was usual with him, to the astonishment of the commanders. Not only before the battle, but in the height of the danger, he showed himself great, and manifested the self-possession of a just foresight and confidence. For the battle for some time fluctuated and was dubious. The left wing, where Parmenio commanded, was so impetuously charged by the Bactrian horse that it was disordered and forced to give ground, at the same time that Mazaeus had sent a detachment around to fall upon those who guarded the baggage, which so disturbed Parmenio, that he sent messengers to acquaint Alexander that the camp and baggage would be all lost unless he immediately relieved the rear by a considerable reinforcement drawn out of the front. This message being brought him just as he was giving the signal to those about him for the onset, he bade them tell Parmenio that he must have surely lost the use of his reason, and had forgotten, in his alarm, that soldiers, if victorious, become masters of their enemies' baggage; and if defeated, instead of taking care of their wealth or their slaves, have nothing more to do but to fight gallantly and die with honor.
When he had said this, he put on his helmet, having the rest of his arms on before he came out of his tent, which were a coat of the Sicilian make, girt close about him, and over that a breastpiece of thickly quilted linen, which was taken among other booty at the battle of Issus. The helmet, which was made by Theophilus, though of iron, was so well wrought and polished, that it was as bright as the most refined silver. To this was fitted a gorget of the same metal, set with precious stones His sword, which was the weapon he most used in fight, was given him by the king of the Citieans, and was of an admirable temper and lightness. The belt which he also wore in all engagements, was of much richer workmanship than the rest of his armor. It was the work of the ancient Helicon, and had been presented to him by the Rhodians, as a mark of their respect to him. So long as he was engaged in drawing up his men, or riding about to give orders or directions, or to view them, he spared Bucephalas, who was now growing old, and made use of another horse; but when he was actually to fight, he sent for him again, and as soon as he was mounted, commenced the attack.
He made the longest address that day to the Thessalians and other Greeks, who answered him with loud shouts desiring him to lead them on against the barbarians, upon which he shifted his javelin into his left hand, and with his right lifted up towards heaven, besought the gods, as Callisthenes tells us, that if he was of a truth the son of Jupiter, they would be pleased to assist and strengthen the Grecians. At the same time the augur Aristander, who had a white mantle about him, and a crown of gold on his head, rode by and showed them an eagle that soared just over Alexander, and directed his flight towards the enemy; which so animated the beholders, that after mutual encouragements and exhortations, the cavalry charged at full speed, and were followed in a mass by the whole phalanx of the foot. But before they could well come to blows with the first ranks, the barbarians shrunk back, and were hotly pursued by Alexander, who drove those that fled before him into the middle of the battle, where Darius himself was in person, whom he saw from a distance over the foremost ranks, conspicuous in the midst of his lifeguard, a tall and fine-looking man, drawn in a lofty chariot, defended by an abundance of the best cavalry who stood close in order about it, ready to receive the enemy. But Alexander's approach was so terrible, forcing those who gave back upon those who yet maintained their ground, that he beat down and dispersed them almost all. Only a few of the bravest and valiantest opposed the pursuit, who were slain in their king's presence, falling in heaps upon one another, and in the very pangs of death striving to catch hold of the horses. Darius now seeing all was lost, that those who were placed in front to defend him were broken and beaten back upon him, that he could not turn or disengage his chariot without great difficulty, the wheels being clogged and entangled among the dead bodies, which lay in such heaps as not only stopped, but almost covered the horses, and made them rear and grow so unruly, that the frighted charioteer could govern them no longer, in this extremity was glad to quit his chariot and his arms, and mounting, it is said, upon a mare that had been taken from her foal, betook himself to flight.
This battle being thus over, seemed to put a period to the Persian empire; and Alexander, who was now proclaimed king of Asia, returned thanks to the gods in magnificent sacrifices, and rewarded his friends and followers with great sums of money, and places, and governments of provinces.
From here he marched through the province of Babylon, which immediately submitted to him, and was much surprised at the sight in one place where fire issues in a continuous stream, like a spring of water, out of a cleft in the earth, and the stream of naphtha, which, not far from this spot, flows out so abundantly as to form a sort of lake. This naphtha, in other respects resembling bitumen, is so subject to take fire, that before it touches the flame, it will kindle at the very light that surrounds it, and often inflame the intermediate air also. The barbarians, to show the power and nature of it, sprinkled the street that led to the king's lodgings with little drops of it, and when it was almost night, stood at the further end with torches, which being applied to the moistened places, the first at once taking fire, instantly, as quick as a man could think of it, it caught from one end to another, in such a manner that the whole street was one continuous flame.