The day was virtually over, yet the hardest fighting of the battle was yet to take place. The Parthian cavalry, with some squadrons of Persian and Indian horse among them, encountered, as they retreated across the field of battle, Alexander himself and the "Companions." Their only hope of escape was to cut through the advancing force. It was no time for tactics, only for a desperate charge for life. Each man was fighting for himself, and he fought with a fury that made him a match even for Macedonian discipline and valour. And the enemy had among them some of the most expert swordsmen in the world. Anyhow, the "Companions" suffered more severely than they did in any other engagement in the war. Sixty were slain in the course of a few minutes, three of the principal officers were wounded, and even Alexander himself was in serious danger. But the Parthians thought only of saving their lives, and when they once saw the way clear before them they were only too glad to follow it. The Persians achieved one more success. A brigade of Indian and Persian horse had plunged through a gap which the movement of the phalanx had left in the line, and attacked the camp. The Thracians who guarded it were hampered by the number of the prisoners whom they had to watch. Many of these escaped. The mother of Darius--the effort had been made for her--might have been one of them, but she refused to go. By this time some troops had come to the rescue of the camp, and the Persian cavalry had to fly. The great battle of Arbela was over. It was the most hardly won as it was the most conclusive of all Alexander's victories. The Persians made no further stand. The great enemy of Greece had disappeared from the stage of history. But we shall find the powerful forces which Persia represented appear again in another shape. _BOOK IV_ ROME AND CARTHAGE I. THE SERVANTS OF MARS