In this hopeless situation, the fainting spirits of the Romans were revived by the sound of peace. The transient presumption of Sapor had vanished: he observed with serious concern, that in the repetition of doubtful combats, he had lost his most faithful and intrepid nobles, his bravest troops, and the greatest part of his train of elephants; and the experienced monarch feared to provoke the resistance of despair, the vicissitudes of fortune, and the unexhausted powers of the Roman Empire; which might soon advance to relieve, or to revenge, the successor of Julian. The Surenas himself, accompanied by another satrap, appeared in the camp of Jovian; and declared that the clemency of his sovereign was not averse to signify the conditions on which he would consent to spare and to dismiss the cæsar, with the relics of his captive army. The hopes of safety subdued the firmness of the Romans; the emperor was compelled, by the advice of his council, and the cries of his soldiers, to embrace the offer of peace; and the prefect Sallust was immediately sent, with the general Arinthæus, to understand the pleasure of the Great King. The crafty Persian delayed, under various pretences, the conclusion of the agreement; started difficulties, required explanations, suggested expedients, receded from his concessions, increased his demands, and wasted four days in the arts of negotiation, till he had consumed the stock of provisions which yet remained in the camp of the Romans. Had Jovian been capable of executing a bold and prudent measure, he would have continued his march with unremitting diligence; the progress of the treaty would have suspended the attacks of the barbarians; and, before the expiration of the fourth day, he might have safely reached the fruitful province of Gordyene, at the distance of only one hundred miles. The irresolute emperor, instead of breaking through the toils of the enemy, expected his fate with patient resignation; and accepted the humiliating conditions of peace, which it was no longer in his power to refuse.
As the price of his disgraceful concessions, the emperor might perhaps have stipulated, that the camp of the hungry Romans should be plentifully supplied; and that they should be permitted to pass the Tigris on the bridge which was constructed by the hands of the Persians. But if Jovian presumed to solicit those equitable terms, they were sternly refused by the haughty tyrant of the East whose clemency had pardoned the invaders of his country. The Saracens sometimes intercepted the stragglers of the march; but the generals and troops of Sapor respected the cessation of arms, and Jovian was suffered to explore the most convenient place for the passage of the river.
“But when the trumpets openly gave the signal for crossing the river,” says Ammianus, “it was dreadful to see with what ardour every individual hastened to rush into this danger, preferring himself to all his comrades in the desire of avoiding the many dangers and distresses behind him. Some tried to guide the beasts who were swimming about at random, with hurdles hurriedly put together; others, seated on bladders, and others, being driven by necessity to all kinds of expedients, sought to pass through the opposing waves by crossing them obliquely. The emperor himself with a few others crossed over in the small boats, which we said were saved when the fleet was burnt, and then sent the same vessels backwards and forwards till our whole body was brought across. And at length all of us, except such as were drowned, reached the opposite bank of the river, being saved amid our difficulties by the favour of the Supreme Deity.”
As soon as the Romans had landed on the western bank, they were delivered from the hostile pursuit of the barbarians; but, in a laborious march of two hundred miles over the plains of Mesopotamia, they endured the last extremities of thirst and hunger. At Thilsaphata, the emperor most graciously received the generals of Mesopotamia; and the remains of a once flourishing army at length reposed themselves under the walls of Nisibis. The messengers of Jovian had proclaimed, in the language of flattery, his election, his treaty, and his return; and the new prince had taken the most effectual measures to secure the allegiance of the armies and provinces of Europe, by placing the military command in the hands of those officers who, from motives of interest or inclination, would firmly support the cause of their benefactor.