their bishop,
[65] inured to arms by the presence of danger, and convinced of the
intentions of Sapor to plant a Persian colony in their room, and to lead
them away into distant and barbarous captivity. The event of the two
former sieges elated their confidence, and exasperated the haughty
spirit of the Great King, who advanced a third time towards Nisibis,
at the head of the united forces of Persia and India. The ordinary
machines, invented to batter or undermine the walls, were rendered
ineffectual by the superior skill of the Romans; and many days had
vainly elapsed, when Sapor embraced a resolution worthy of an eastern
monarch, who believed that the elements themselves were subject to his
power. At the stated season of the melting of the snows in Armenia, the
River Mygdonius, which divides the plain and the city of Nisibis, forms,
like the Nile, [66] an inundation over the adjacent country. By the
labor of the Persians, the course of the river was stopped below the
town, and the waters were confined on every side by solid mounds of
earth. On this artificial lake, a fleet of armed vessels filled with
soldiers, and with engines which discharged stones of five hundred
pounds weight, advanced in order of battle, and engaged, almost upon a
level, the troops which defended the ramparts. [66a] The irresistible
force of the waters was alternately fatal to the contending parties,
till at length a portion of the walls, unable to sustain the accumulated
pressure, gave way at once, and exposed an ample breach of one hundred
and fifty feet. The Persians were instantly driven to the assault, and
the fate of Nisibis depended on the event of the day. The heavy-armed
cavalry, who led the van of a deep column, were embarrassed in the mud,
and great numbers were drowned in the unseen holes which had been filled
by the rushing waters. The elephants, made furious by their wounds,
increased the disorder, and trampled down thousands of the Persian
archers. The Great King, who, from an exalted throne, beheld the
misfortunes of his arms, sounded, with reluctant indignation, the signal
of the retreat, and suspended for some hours the prosecution of the
attack. But the vigilant citizens improved the opportunity of the night;
and the return of day discovered a new wall of six feet in
height, rising every moment to fill up the interval of the breach.
Notwithstanding the disappointment of his hopes, and the loss of more
than twenty thousand men,