ssed was brought
into play. Besides the three arms of cavalry, infantry, and chariots,
elephants were, for perhaps the first time in the history of military
science, marshalled in the battle-field, to which they added an unwonted
element of grotesqueness and savagery.

The field of battle was likewise selected with great care, and
artificially prepared for the encounter. Darius, it would seem, had
at last become convinced that his enemy would seek him out wherever he
might happen to be, and that consequently the choice of ground rested
wholly with himself. Leaving, therefore, the direct road to Babylon
by the line of the Euphrates undefended, he selected a position which
possessed all the advantages of the Mesopotamian plain, being open,
level, fertile, and well supplied with water, while its vicinity to the
eastern and northern provinces, made it convenient for a rendezvous.
This position was on the left or east bank of the Tigris, in the heart
of the ancient Assyria, not more than thirty miles from the site of
Nineveh. Here, in the region called by the Greeks Adiabene, extended
between the Tigris and the river Zab or Lycus, a vast plain broken by
scarcely any elevations, and wholly bare of both shrubs and trees. The
few natural inequalities which presented themselves were levelled by
order of Darius, who made the entire plain in his front practicable not
only for cavalry but for chariots. At the same time he planted, in the
places where Alexander's cavalry was likely to charge, spiked balls to
damage the feet of the horses.

Meanwhile, Alexander had quitted Egypt, and after delaying some months
in Syria while his preparations were being completed, had crossed the
Euphrates at Thapsacus and marched through northern Mesopotamia along
the southern flank of the Mons Masius, a district in which provisions,
water, and forage were abundant, to the Tigris, which he must have
reached in about lat. 36 deg. 30', thirty or forty miles above the site of
Nineveh. No resistance was made to his advance; even the passage of
the great rivers was unopposed. Arrived on the east bank of the Tigris,
Alexander found himself in Assyria Proper, with the stream upon his
right and the mountains of Gordyene Kurdistan at no great distance upon
his left. But the plain widened as he advanced, and became, as he drew
near the position of his enemy, a vast level, nowhere less than thirty
miles in breadth, between the outlying ranges of hills and the