The voice of the dying emperor had recommended the care of his funeral to the piety of Constantius; and that prince, by the vicinity of his eastern station, could easily prevent the diligence of his brothers, who resided in their distant government of Italy and Gaul. As soon as he had taken possession of the palace of Constantinople, his first care was to remove the apprehensions of his kinsmen, by a solemn oath which he pledged for their security. His next employment was to find some specious pretence which might release his conscience from the obligation of an imprudent promise. The arts of fraud were made subservient to the designs of cruelty; and a manifest forgery was attested by a person of the most sacred character. From the hands of the Bishop of Nicomedia, Constantius received a fatal scroll, affirmed to be the genuine testament of his father; in which the emperor expressed his suspicions that he had been poisoned by his brothers; and conjured his sons to revenge his death, and to consult their own safety, by the punishment of the guilty. Whatever reasons might have been alleged by these unfortunate princes to defend their life and honor against so incredible an accusation, they were silenced by the furious clamors of the soldiers, who declared themselves, at once, their enemies, their judges, and their executioners. The spirit, and even the forms of legal proceedings were repeatedly violated in a promiscuous massacre; which involved the two uncles of Constantius, seven of his cousins, of whom Dalmatius and Hannibalianus were the most illustrious, the Patrician Optatus, who had married a sister of the late emperor, and the Præfect Ablavius, whose power and riches had inspired him with some hopes of obtaining the purple. If it were necessary to aggravate the horrors of this bloody scene, we might add, that Constantius himself had espoused the daughter of his uncle Julius, and that he had bestowed his sister in marriage on his cousin Hannibalianus. These alliances, which the policy of Constantine, regardless of the public prejudice, had formed between the several branches of the Imperial house, served only to convince mankind, that these princes were as cold to the endearments of conjugal affection, as they were insensible to the ties of consanguinity, and the moving entreaties of youth and innocence. Of so numerous a family, Gallus and Julian alone, the two youngest children of Julius Constantius, were saved from the hands of the assassins, till their rage, satiated with slaughter, had in some measure subsided. The emperor Constantius, who, in the absence of his brothers, was the most obnoxious to guilt and reproach, discovered, on some future occasions, a faint and transient remorse for those cruelties which the perfidious counsels of his ministers, and the irresistible violence of the troops, had extorted from his unexperienced youth.
The massacre of the Flavian race was succeeded by a new division of the provinces; which was ratified in a personal interview of the three brothers. Constantine, the eldest of the Cæsars, obtained, with a certain preeminence of rank, the possession of the new capital, which bore his own name and that of his father. Thrace, and the countries of the East, were allotted for the patrimony of Constantius; and Constans was acknowledged as the lawful sovereign of Italy, Africa, and the Western Illyricum. The armies submitted to their hereditary right; and they condescended, after some delay, to accept from the Roman senate the title of Augustus. When they first assumed the reins of government, the eldest of these princes was twenty-one, the second twenty, and the third only seventeen, years of age.
While the martial nations of Europe followed the standards of his brothers, Constantius, at the head of the effeminate troops of Asia, was left to sustain the weight of the Persian war. At the decease of Constantine, the throne of the East was filled by Sapor, son of Hormouz, or Hormisdas, and grandson of Narses, who, after the victory of Galerius, had humbly confessed the superiority of the Roman power. Although Sapor was in the thirtieth year of his long reign, he was still in the vigor of youth, as the date of his accession, by a very strange fatality, had preceded that of his birth. The wife of Hormouz remained pregnant at the time of her husband's death; and the uncertainty of the sex, as well as of the event, excited the ambitious hopes of the princes of the house of Sassan. The apprehensions of civil war were at length removed, by the positive assurance of the Magi, that the widow of Hormouz had conceived, and would safely produce a son. Obedient to the voice of superstition, the Persians prepared, without delay, the ceremony of his coronation. A royal bed, on which the queen lay in state, was exhibited in the midst of the palace; the diadem was placed on the spot, which might be supposed to conceal the future heir of Artaxerxes, and the prostrate satraps adored the majesty of their invisible and insensible sovereign. If any credit can be given to this marvellous tale, which seems, however, to be countenanced by the manners of the people, and by the extraordinary duration of his reign, we must admire not only the fortune, but the genius, of Sapor. In the soft, sequestered education of a Persian harem, the royal youth could discover the importance of exercising the vigor of his mind and body; and, by his personal merit, deserved a throne, on which he had been seated, while he was yet unconscious of the duties and temptations of absolute power. His minority was exposed to the almost inevitable calamities of domestic discord; his capital was surprised and plundered by Thair, a powerful king of Yemen, or Arabia; and the majesty of the royal family was degraded by the captivity of a princess, the sister of the deceased king. But as soon as Sapor attained the age of manhood, the presumptuous Thair, his nation, and his country, fell beneath the first effort of the young warrior; who used his victory with so judicious a mixture of rigor and clemency, that he obtained from the fears and gratitude of the Arabs the title of Dhoulacnaf, or protector of the nation.
The ambition of the Persian, to whom his enemies ascribe the virtues of a soldier and a statesman, was animated by the desire of revenging the disgrace of his fathers, and of wresting from the hands of the Romans the five provinces beyond the Tigris. The military fame of Constantine, and the real or apparent strength of his government, suspended the attack; and while the hostile conduct of Sapor provoked the resentment, his artful negotiations amused the patience of the Imperial court. The death of Constantine was the signal of war, and the actual condition of the Syrian and Armenian frontier seemed to encourage the Persians by the prospect of a rich spoil and an easy conquest. The example of the massacres of the palace diffused a spirit of licentiousness and sedition among the troops of the East, who were no longer restrained by their habits of obedience to a veteran commander. By the prudence of Constantius, who, from the interview with his brothers in Pannonia, immediately hastened to the banks of the Euphrates, the legions were gradually restored to a sense of duty and discipline; but the season of anarchy had permitted Sapor to form the siege of Nisibis, and to occupy several of the most important fortresses of Mesopotamia. In Armenia, the renowned Tiridates had long enjoyed the peace and glory which he deserved by his valor and fidelity to the cause of Rome. The firm alliance which he maintained with Constantine was productive of spiritual as well as of temporal benefits; by the conversion of Tiridates, the character of a saint was applied to that of a hero, the Christian faith was preached and established from the Euphrates to the shores of the Caspian, and Armenia was attached to the empire by the double ties of policy and religion. But as many of the Armenian nobles still refused to abandon the plurality of their gods and of their wives, the public tranquillity was disturbed by a discontented faction, which insulted the feeble age of their sovereign, and impatiently expected the hour of his death. He died at length after a reign of fifty-six years, and the fortune of the Armenian monarchy expired with Tiridates. His lawful heir was driven into exile, the Christian priests were either murdered or expelled from their churches, the barbarous tribes of Albania were solicited to descend from their mountains; and two of the most powerful governors, usurping the ensigns or the powers of royalty, implored the assistance of Sapor, and opened the gates of their cities to the Persian garrisons. The Christian party, under the guidance of the Archbishop of Artaxata, the immediate successor of St. Gregory the Illuminator, had recourse to the piety of Constantius. After the troubles had continued about three years, Antiochus, one of the officers of the household, executed with success the Imperial commission of restoring Chosroes, * the son of Tiridates, to the throne of his fathers, of distributing honors and rewards among the faithful servants of the house of Arsaces, and of proclaiming a general amnesty, which was accepted by the greater part of the rebellious satraps. But the Romans derived more honor than advantage from this revolution. Chosroes was a prince of a puny stature and a pusillanimous spirit. Unequal to the fatigues of war, averse to the society of mankind, he withdrew from his capital to a retired palace, which he built on the banks of the River Eleutherus, and in the centre of a shady grove; where he consumed his vacant hours in the rural sports of hunting and hawking. To secure this inglorious ease, he submitted to the conditions of peace which Sapor condescended to impose; the payment of an annual tribute, and the restitution of the fertile province of Atropatene, which the courage of Tiridates, and the victorious arms of Galerius, had annexed to the Armenian monarchy.
During the long period of the reign of Constantius, the provinces of the East were afflicted by the calamities of the Persian war. The irregular incursions of the light troops alternately spread terror and devastation beyond the Tigris and beyond the Euphrates, from the gates of Ctesiphon to those of Antioch; and this active service was performed by the Arabs of the desert, who were divided in their interest and affections; some of their independent chiefs being enlisted in the party of Sapor, whilst others had engaged their doubtful fidelity to the emperor. The more grave and important operations of the war were conducted with equal vigor; and the armies of Rome and Persia encountered each other in nine bloody fields, in two of which Constantius himself commanded in person. The event of the day was most commonly adverse to the Romans, but in the battle of Singara, heir imprudent valor had almost achieved a signal and decisive victory. The stationary troops of Singara * retired on the approach of Sapor, who passed the Tigris over three bridges, and occupied near the village of Hilleh an advantageous camp, which, by the labor of his numerous pioneers, he surrounded in one day with a deep ditch and a lofty rampart. His formidable host, when it was drawn out in order of battle, covered the banks of the river, the adjacent heights, and the whole extent of a plain of above twelve miles, which separated the two armies. Both were alike impatient to engage; but the Barbarians, after a slight resistance, fled in disorder; unable to resist, or desirous to weary, the strength of the heavy legions, who, fainting with heat and thirst, pursued them across the plain, and cut in pieces a line of cavalry, clothed in complete armor, which had been posted before the gates of the camp to protect their retreat. Constantius, who was hurried along in the pursuit, attempted, without effect, to restrain the ardor of his troops, by representing to them the dangers of the approaching night, and the certainty of completing their success with the return of day. As they depended much more on their own valor than on the experience or the abilities of their chief, they silenced by their clamors his timid remonstrances; and rushing with fury to the charge, filled up the ditch, broke down the rampart, and dispersed themselves through the tents to recruit their exhausted strength, and to enjoy the rich harvest of their labors. But the prudent Sapor had watched the moment of victory. His army, of which the greater part, securely posted on the heights, had been spectators of the action, advanced in silence, and under the shadow of the night; and his Persian archers, guided by the illumination of the camp, poured a shower of arrows on a disarmed and licentious crowd. The sincerity of history declares, that the Romans were vanquished with a dreadful slaughter, and that the flying remnant of the legions was exposed to the most intolerable hardships. Even the tenderness of panegyric, confessing that the glory of the emperor was sullied by the disobedience of his soldiers, chooses to draw a veil over the circumstances of this melancholy retreat. Yet one of those venal orators, so jealous of the fame of Constantius, relates, with amazing coolness, an act of such incredible cruelty, as, in the judgment of posterity, must imprint a far deeper stain on the honor of the Imperial name. The son of Sapor, the heir of his crown, had been made a captive in the Persian camp. The unhappy youth, who might have excited the compassion of the most savage enemy, was scourged, tortured, and publicly executed by the inhuman Romans.
Whatever advantages might attend the arms of Sapor in the field, though nine repeated victories diffused among the nations the fame of his valor and conduct, he could not hope to succeed in the execution of his designs, while the fortified towns of Mesopotamia, and, above all, the strong and ancient city of Nisibis, remained in the possession of the Romans. In the space of twelve years, Nisibis, which, since the time of Lucullus, had been deservedly esteemed the bulwark of the East, sustained three memorable sieges against the power of Sapor; and the disappointed monarch, after urging his attacks above sixty, eighty, and a hundred days, was thrice repulsed with loss and ignominy. This large and populous city was situate about two days' journey from the Tigris, in the midst of a pleasant and fertile plain at the foot of Mount Masius. A treble enclosure of brick walls was defended by a deep ditch; and the intrepid resistance of Count Lucilianus, and his garrison, was seconded by the desperate courage of the people. The citizens of Nisibis were animated by the exhortations of their bishop, 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, 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. *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. 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.
After the partition of the empire, three years had scarcely elapsed before the sons of Constantine seemed impatient to convince mankind that they were incapable of contenting themselves with the dominions which they were unqualified to govern. The eldest of those princes soon complained, that he was defrauded of his just proportion of the spoils of their murdered kinsmen; and though he might yield to the superior guilt and merit of Constantius, he exacted from Constans the cession of the African provinces, as an equivalent for the rich countries of Macedonia and Greece, which his brother had acquired by the death of Dalmatius. The want of sincerity, which Constantine experienced in a tedious and fruitless negotiation, exasperated the fierceness of his temper; and he eagerly listened to those favorites, who suggested to him that his honor, as well as his interest, was concerned in the prosecution of the quarrel. At the head of a tumultuary band, suited for rapine rather than for conquest, he suddenly broke onto the dominions of Constans, by the way of the Julian Alps, and the country round Aquileia felt the first effects of his resentment. The measures of Constans, who then resided in Dacia, were directed with more prudence and ability. On the news of his brother's invasion, he detached a select and disciplined body of his Illyrian troops, proposing to follow them in person, with the remainder of his forces. But the conduct of his lieutenants soon terminated the unnatural contest. By the artful appearances of flight, Constantine was betrayed into an ambuscade, which had been concealed in a wood, where the rash youth, with a few attendants, was surprised, surrounded, and slain. His body, after it had been found in the obscure stream of the Alsa, obtained the honors of an Imperial sepulchre; but his provinces transferred their allegiance to the conqueror, who, refusing to admit his elder brother Constantius to any share in these new acquisitions, maintained the undisputed possession of more than two thirds of the Roman empire.