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. 6611 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, Sapor still pressed the reduction of Nisibis, with an obstinate firmness, which could have yielded only to the necessity of defending the eastern provinces of Persia against a formidable invasion of the Massagetæ. 67 Alarmed by this intelligence, he hastily relinquished the siege, and marched with rapid diligence from the banks of the Tigris to those of the Oxus. The danger and difficulties of the Scythian war engaged him soon afterwards to conclude, or at least to observe, a truce with the Roman emperor, which was equally grateful to both princes; as Constantius himself, after the death of his two brothers, was involved, by the revolutions of the West, in a civil contest, which required and seemed to exceed the most vigorous exertion of his undivided strength. 63 (return) [ See Julian. Orat. i. p. 27, Orat. ii. p. 62, &c., with the Commentary of Spanheim, (p. 188-202,) who illustrates the circumstances, and ascertains the time of the three sieges of Nisibis. Their dates are likewise examined by Tillemont, (Hist. des Empereurs, tom. iv. p. 668, 671, 674.) Something is added from Zosimus, l. iii. p. 151, and the Alexandrine Chronicle, p. 290.]