The Historians' History of the World 04 [Greece to the Roman Conquest]

The Persian king had employed the long interval allowed him by Alexander’s operations after the battle of Issus, to collect the remaining strength of his empire; and he had assembled a host with which, if superiority of numbers could have ensured success, he might reasonably have hoped to crush his adversary. It was also composed for the most part of more warlike troops. The division which was most formidable, both for numbers and martial qualities, consisted of the hardy tribes which inhabited the plains on the eastern side of the Caspian, and the valleys above Cabul on the borders of India. They were led by Bessus, the powerful satrap of Bactria; and he was also followed by a body of horse-bowmen, furnished by the Sacæ, who wandered in the valleys east of Transoxiana, and though they did not acknowledge his authority, willingly joined him as allies for the sake of pay and plunder. All the provinces between the Caspian Sea and the Persian Gulf, and from Syria and Cappadocia to the mountains west of the Indus, had poured forth their choicest warriors.

The whole amount was stated by some authors at a million of foot and forty thousand horse; this may be a great exaggeration, but it was probably reduced as much too low by those who reckoned no more than two hundred thousand infantry. There were beside two hundred scythed chariots, and fifteen elephants brought from the west of India. With this host Darius had encamped in one of the wide plains between the Tigris and the mountains of Kurdistan, near the Bumadus, a tributary of the Lycus, and a village named Gaugamela (the camel’s house), which should have given its name to the battle fought near it, but was forced, through a caprice of which we have many examples, to surrender this distinction to the town of Arbela, which lay more than twenty miles off, where Darius had left his baggage and his treasure. He had been persuaded by his courtiers that his defeat at Issus was entirely owing to the disadvantage of the ground, and he had therefore chosen a field on which he might fully display his forces, and where the enemy would have neither sea nor mountains to cover his flanks; and he had ordered a large tract of the plain to be cleared and levelled for the evolutions of his cavalry and chariots.d

THE BATTLE OF ARBELA

The position of the Persian king near Mesopotamia was chosen with great military skill. It was certain that Alexander on his return from Egypt must march northward along the Syrian coast, before he attacked the central provinces of the Persian empire. A direct eastward march from the lower part of Palestine across the great Syrian desert was then, as now, utterly impracticable. Marching eastward from Syria, Alexander would, on crossing the Euphrates, arrive at the vast Mesopotamian plains. The wealthy capitals of the empire, Babylon, Susa, and Persepolis, would then lie to his south; and if he marched down through Mesopotamia to attack them, Darius might reasonably hope to follow the Macedonians with his immense force of cavalry, and, without even risking a pitched battle, to harass and finally overwhelm them. We may remember that three centuries afterwards a Roman army under Crassus was thus actually destroyed by the oriental archers and horsemen in these very plains; and that the ancestors of the Parthians who thus vanquished the Roman legions, served by thousands under King Darius. If, on the contrary, Alexander should defer his march against Babylon, and first seek an encounter with the Persian army, the country on each side of the Tigris in this latitude was highly advantageous for such an army as Darius commanded; and he had close in his rear the mountainous districts of northern Media, where he himself had in early life been satrap, where he had acquired reputation as a soldier and a general, and where he justly expected to find loyalty to his person, and a safe refuge in case of defeat.