The Seven Great Monarchies: The Sassanian or New Persian Empire
George Rawlinson author
Revolt of Armenia and Acceptance by Arsaces of the Position of a Roman Feudatory. Character and Issue of Sapor's Eastern Wars. His negotiations with Constantius. His Extreme Demands. Circumstances under which he determines to renew the War. His Preparations. Desertion to him of Antoninus. Great Invasion of Sapor. Siege of Amida. Sapor's Severities. Siege and Capture of Singara; of Bezabde. Attack on Virtu fails. Aggressive Movement of Constantius. He attacks Bezabde, but fails Campaign of A.D. 361. Death of Constantius.
Evenerat . . . quasi fatali constellatione . . . ut Constantium dimicantem cum Persis fortuna semper sequeretur afflictior.—Amm. Marc. xx. 9, ad fin.
It seems to have been soon after the close of Sapor's first war with Constantius that events took place in Armenia which once more replaced that country under Roman influence. Arsaces, the son of Tiranus, had been, as we have seen, established as monarch, by Sapor, in the year A.D. 341, under the notion that, in return for the favor shown him, he would administer Armenia in the Persian interest. But gratitude is an unsafe basis for the friendships of monarchs. Arsaces, after a time, began to chafe against the obligations under which Sapor had laid him, and to wish, by taking independent action, to show himself a real king, and not a mere feudatory. He was also, perhaps, tired of aiding Sapor in his Roman war, and may have found that he suffered more than he gained by having Rome for an enemy. At any rate, in the interval between A.D. 351 and 359, probably while Sapor was engaged in the far East, Arsaces sent envoys to Constantinople with a request to Constantius that he would give him in marriage a member of the Imperial house. Constantius was charmed with the application made to him, and at once accepted the proposal. He selected for the proffered honor a certain Olympias, the daughter of Ablabius, a Praetorian prefect, and lately the betrothed bride of his own brother, Constans; and sent her to Armenia, where Arsaces welcomed her, and made her (as it would seem) his chief wife, provoking thereby the jealousy and aversion of his previous sultana, a native Armenian, named Pharandzem. The engagement thus entered into led on, naturally, to the conclusion of a formal alliance between Rome and Armenia—an alliance which Sapor made fruitless efforts to disturb, and which continued unimpaired down to the time A.D. 359 when hostilities once more broke out between Rome and Persia.
Of Sapor's Eastern wars we have no detailed account. They seem to have occupied him from A.D. 350 to A.D. 357, and to have been, on the whole, successful. They were certainly terminated by a peace in the last-named year—a peace of which it must have been a condition that his late enemies should lend him aid in the struggle which he was about to renew with Rome. Who these enemies exactly were, and what exact region they inhabited, is doubtful. They comprised certainly the Chionites and Gelani, probably the Euseni and the Vertse. The Chionites are thought to have been Hiongnu or Huns; and the Euseni are probably the Usiun, who, as early as B.C. 200, are found among the nomadic hordes pressing towards the Oxus. The Vertse are wholly unknown. The Gelani should, by their name, be the inhabitants of Ghilan, or the coast tract south-west of the Caspian; but this locality seems too remote from the probable seats of the Chionites and Euseni to be the one intended. The general scene of the wars was undoubtedly east of the Caspian, either in the Oxus region, or still further eastward, on the confines of India and Scythia. The result of the wars, though not a conquest, was an extension of Persian influence and power. Troublesome enemies were converted into friends and allies. The loss of a predominating influence over Armenia was thus compensated, or more than compensated, within a few years, by a gain of a similar kind in another quarter.
While Sapor was thus engaged in the far East, he received letters from the officer whom he had left in charge of his western frontier, informing him that the Romans were anxious to exchange the precarious truce which Mesopotamia had been allowed to enjoy during the last five or six years for a more settled and formal peace. Two great Roman officials, Cassianus, duke of Mesopotamia, and Musonianus, Praetorian prefect, understanding that Sapor was entangled in a bloody and difficult war at the eastern extremity of his empire, and knowing that Constantius was fully occupied with the troubles caused by the inroads of the barbarians into the more western of the Roman provinces, had thought that the time was favorable for terminating the provisional state of affairs in the Mesopotamian region by an actual treaty. They had accordingly opened negotiations with Tamsapor, satrap of Adiabene, and suggested to him that he should sound his master on the subject of making peace with Rome. Tamsapor appears to have misunderstood the character of these overtures, or to have misrepresented them to Sapor; in his despatch he made Constantius himself the mover in the matter, and spoke of him as humbly supplicating the great king to grant him conditions. It happened that the message reached Sapor just as he had come to terms with his eastern enemies, and had succeeded in inducing them to become his allies. He was naturally elated at his success, and regarded the Roman overture as a simple acknowledgment of weakness. Accordingly he answered in the most haughty style. His letter, which was conveyed to the Roman emperor at Sirmium by an ambassador named Narses, was conceived in the following terms:
"Sapor, king of kings, brother of the sun and moon, and companion of the stars, sends salutation to his brother, Constantius Caesar. It glads me to see that thou art at last returned to the right way, and art ready to do what is just and fair, having learned by experience that inordinate greed is oft-times punished by defeat and disaster. As then the voice of truth ought to speak with all openness, and the more illustrious of mankind should make their words mirror their thoughts, I will briefly declare to thee what I propose, not forgetting that I have often said the same things before. Your own authors are witness that the entire tract within the river Strymon and the borders of Macedon was once held by my ancestors; if I required you to restore all this, it would not ill become me (excuse the boast), inasmuch as I excel in virtue and in the splendor of my achievements the whole line of our ancient monarchs. But as moderation delights me, and has always been the rule of my conduct—wherefore from my youth up I have had no occasion to repent of any action—I will be content to receive Mesopotamia and Armenia, which was fraudulently extorted from my grandfather. We Persians have never admitted the principle, which you proclaim with such effrontery, that success in war is always glorious, whether it be the fruit of courage or trickery. In conclusion, if you will take the advice of one who speaks for your good, sacrifice a small tract of territory, one always in dispute and causing continual bloodshed, in order that you may rule the remainder securely. Physicians, remember, often cut and burn, and even amputate portions of the body, that the patient may have the healthy use of what is left to him; and there are animals which, understanding why the hunters chase them, deprive themselves of the thing coveted, to live thenceforth without fear. I warn you, that, if my ambassador returns in vain, I will take the field against you, so soon as the winter is past, with all my forces, confiding in my good fortune and in the fairness of the conditions which I have now offered."
It must have been a severe blow to Imperial pride to receive such a letter: and the sense of insult can scarcely have been much mitigated by the fact that the missive was enveloped in a silken covering, or by the circumstance that the bearer, Narses, endeavored by his conciliating manners to atone for his master's rudeness. Constantius replied, however, in a dignified and calm tone. "The Roman emperor," he said, "victorious by land and sea, saluted his brother, King Sapor. His lieutenant in Mesopotamia had meant well in opening a negotiation with a Persian governor; but he had acted without orders, and could not bind his master. Nevertheless, he (Constantius) would not disclaim what had been done, since he did not object to a peace, provided it were fair and honorable. But to ask the master of the whole Roman world to surrender territories which he had successfully defended when he ruled only over the provinces of the East was plainly indecent and absurd. He must add that the employment of threats was futile, and too common an artifice; more especially as the Persians themselves must know that Rome always defended herself when attacked, and that, if occasionally she was vanquished in a battle, yet she never failed to have the advantage in the event of every war." Three envoys were entrusted with the delivery of this reply—Prosper, a count of the empire; Spectatus, a tribune and notary; and Eustathius, an orator and philosopher, a pupil of the celebrated Neo-Platonist, Jamblichus, and a friend of St. Basil. Constantius was most anxious for peace, as a dangerous war threatened with the Alemanni, one of the most powerful tribes of Germany. He seems to have hoped that, if the unadorned language of the two statesmen failed to move Sapor, he might be won over by the persuasive eloquence of the professor of rhetoric.
But Sapor was bent on war. He had concluded arrangements with the natives so long his adversaries in the East, by which they had pledged themselves to join his standard with all their forces in the ensuing spring. He was well aware of the position of Constantius in the West, of the internal corruption of his court, and of the perils constantly threatening him from external enemies. A Roman official of importance, bearing the once honored name of Antoninus, had recently taken refuge with him from the claims of pretended creditors, and had been received into high favor on account of the information which he was able to communicate with respect to the disposition of the Roman forces and the condition of their magazines. This individual, ennobled by the royal authority, and given a place at the royal table, gained great influence over his new master, whom he stimulated by alternately reproaching him with his backwardness in the past, and putting before him the prospect of easy triumphs over Rome in the future. He pointed out that the emperor, with the bulk of his troops and treasures, was detained in the regions adjoining the Danube, and that the East was left almost undefended; he magnified the services which he was himself competent to render; he exhorted Sapor to bestir himself, and to put confidence in his good fortune. He recommended that the old plan of sitting down before walled towns should be given up, and that the Persian monarch, leaving the strongholds of Mesopotamia in his rear, should press forward to the Euphrates, pour his troops across it, and overrun the rich province of Syria, which he would find unguarded, and which had not been invaded by an enemy for nearly a century. The views of Antoninus were adopted; but, in practice, they were overruled by the exigencies of the situation. A Roman army occupied Mesopotamia, and advanced to the banks of the Tigris. When the Persians in full force crossed the river, accompanied by Chionite and Albanian allies, they found a considerable body of troops prepared to resist them. Their opponents did not, indeed offer battle, but they laid waste the country as the Persians took possession of it; they destroyed the forage, evacuated the indefensible towns (which fell, of course, into the enemy's hands), and fortified the line of the Euphrates with castles, military engines, and palisades. Still the programme of Antoninus would probably have been carried out, had not the swell of the Euphrates exceeded the average, and rendered it impossible for the Persian troops to ford the river at the usual point of passage into Syria. On discovering this obstacle, Antoninus suggested that, by a march to the north-east through a fertile country, the "Upper Euphrates" might be reached, and easily crossed, before its waters had attained any considerable volume. Sapor agreed to adopt this suggestion. He marched from Zeugma across the Mons Masius towards the Upper Euphrates, defeated the Romans in an important battle near Arnida, took, by a sudden assault, two castles which defended the town, and then somewhat hastily resolved that he would attack the place, which he did not imagine capable of making much resistance.
Amida, now Diarbekr, was situated on the right bank of the Upper Tigris, in a fertile plain, and was washed along the whole of its western side by a semi-circular bend of the river. It had been a place of considerable importance from a very ancient date, and had recently been much strengthened by Constantius, who had made it an arsenal for military engines, and had repaired its towers and walls. The town contained within it a copious fountain of water, which was liable, however, to acquire a disagreeable odor in the summer time. Seven legions, of the moderate strength to which legions had been reduced by Constantine, defended it; and the garrison included also a body of horse-archers, composed chiefly or entirely of noble foreigners. Sapor hoped in the first instance to terrify it into submission by his mere appearance, and boldly rode up to the gates with a small body of his followers, expecting that they would be opened to him. But the defenders were more courageous than he had imagined. They received him with a shower of darts and arrows that were directed specially against his person, which was conspicuous from its ornaments; and they aimed their weapons so well that one of them passed through a portion of his dress and was nearly wounding him. Persuaded by his followers, Sapor upon this withdrew, and committed the further prosecution of the attack to Grumbates, the king of the Chionites, who assaulted the walls on the next day with a body of picked troops, but was repulsed with great loss, his only son, a youth of great promise, being killed at his side by a dart from a balista. The death of this prince spread dismay through the camp, and was followed by a general mourning; but it now became a point of honor to take the town which had so injured one of the great king's royal allies; and Grumbates was promised that Amida should become the funeral pile of his lost darling.
The town was now regularly invested. Each nation was assigned its place. The Chionites, burning with the desire to avenge their late defeat, were on the east; the Vertse on the south; the Albanians, warriors from the Caspian region, on the north; the Segestans, who were reckoned the bravest soldiers of all, and who brought into the field a large body of elephants, held the west. A continuous line of Persians, five ranks deep, surrounded the entire city, and supported the auxiliary detachments. The entire besieging army was estimated at a hundred thousand men; the besieged, including the unarmed multitude, were under 30,000. After the pause of an entire day, the first general attack was made. Grumbates gave the signal for the assault by hurling a bloody spear into the space before the walls, after the fashion of a Roman fetialis. A cloud of darts and arrows from every side followed the flight of this weapon, and did severe damage to the besieged, who were at the same time galled with discharges from Roman military engines, taken by the Persians in some capture of Singara, and now employed against their former owners. Still a vigorous resistance continued to be made, and the besiegers, in their exposed positions, suffered even more than the garrison; so that after two days the attempt to carry the city by general assault was abandoned, and the slow process of a regular siege was adopted. Trenches were opened at the usual distance from the walls, along which the troops advanced under the cover of hurdles towards the ditch, which they proceeded to fill up in places. Mounds were then thrown up against the walls; and movable towers were constructed and brought into play, guarded externally with iron, and each mounting a balista. It was impossible long to withstand these various weapons of attack. The hopes of the besieged lay, primarily, in their receiving relief from without by the advance of an army capable of engaging their assailants and harassing them or driving them off; secondarily, in successful sallies, by means of which they might destroy the enemy's works and induce him to retire from before the place.
There existed, in the neighborhood of Amida, the elements of a relieving army, under the command of the new prefect of the East, Sabinianus. Had this officer possessed an energetic and enterprising character, he might, without much difficulty, have collected a force of light and active soldiers, which might have hung upon the rear of the Persians, intercepted their convoys, cut off their stragglers, and have even made an occasional dash upon their lines. Such was the course of conduct recommended by Ursicinus, the second in command, whom Sabinianus had recently superseded; but the latter was jealous of his subordinate, and had orders from the Byzantine court to keep him unemployed. He was himself old and rich, alike disinclined to and unfit for military enterprise; he therefore absolutely rejected the advice of Ursicinus, and determined on making no effort. He had positive orders, he said, from the court to keep on the defensive and not endanger his troops by engaging them in hazardous adventures. Amida must protect itself, or at any rate not look to him for succor. Ursicinus chafed terribly, it is said, against this decision, but was forced to submit to it. His messengers conveyed the dispiriting intelligence to the devoted city, which learned thereby that it must rely wholly upon its own exertions.
Nothing now remained but to organize sallies on a large scale and attack the besieger's works. Such attempts were made from time to time with some success; and on one occasion two Gaulish legions, banished to the East for their adherence to the cause of Magnentius, penetrated, by night, into the heart of the besieging camp, and brought the person of the monarch into danger. This peril was, however, escaped; the legions were repulsed with the loss of a sixth of their number; and nothing was gained by the audacious enterprise beyond a truce of three days, during which each side mourned its dead, and sought to repair its losses.
The fate of the doomed city drew on. Pestilence was added to the calamities which the besieged had to endure. Desertion and treachery were arrayed against them. One of the natives of Amida, going over to the Persians, informed them that on the southern side of the city a neglected staircase led up from the margin of the Tigris through underground corridors to one of the principal bastions; and under his guidance seventy archers of the Persian guard, picked men, ascended the dark passage at dead of night, occupied the tower, and when morning broke displayed from it a scarlet flag, as a sign to their countrymen that a portion of the wall was taken. The Persians were upon the alert, and an instant assault was made. But the garrison, by extraordinary efforts, succeeded in recapturing the tower before any support reached its occupants; and then, directing their artillery and missiles against the assailing columns, inflicted on them tremendous losses, and soon compelled them to return hastily to the shelter of their camp. The Verte, who maintained the siege on the south side of the city, were the chief sufferers in this abortive attempt.
Sapor had now spent seventy days before the place, and had made no perceptible impression. Autumn was already far advanced, and the season for military operations would, soon be over. It was necessary, therefore, either to take the city speedily or to give up the siege and retire. Under these circumstances Sapor resolved on a last effort. He had constructed towers of such a height that they overtopped the wall, and poured their discharges on the defenders from a superior elevation. He had brought his mounds in places to a level with the ramparts, and had compelled the garrison to raise countermounds within the walls for their protection. He now determined on pressing the assault day after day, until he either carried the town or found all his resources exhausted. His artillery, his foot, and his elephants were all employed in turn or together; he allowed the garrison no rest. Not content with directing the operations, he himself took part in the supreme struggle, exposing his own person freely to the enemy's weapons, and losing many of his attendants. After the contest had lasted three continuous days from morn to night, fortune at last favored him. One of the inner mounds, raised by the besieged behind their wall, suddenly gave way, involving its defenders in its fall, and at the same time filling up the entire space between the wall and the mound raised outside by the Persians. A way into the town was thus laid open, and the besiegers instantly occupied it. It was in vain that the flower of the garrison threw itself across the path of the entering columns—nothing could withstand the ardor of the Persian troops. In a little time all resistance was at an end; those who could quitted the city and fled—the remainder, whatever their sex, age, or calling, whether armed or unarmed, were slaughtered like sheep by the conquerors.
Thus fell Amida after a siege of seventy-three days. Sapor, who on other occasions showed himself not deficient in clemency, was exasperated by the prolonged resistance and the losses which he had sustained in the course of it. Thirty thousand of his best soldiers had fallen; the son of his chief ally had perished; he himself had been brought into imminent danger. Such audacity on the part of a petty town seemed no doubt to him to deserve a severe retribution. The place was therefore given over to the infuriated soldiery, who were allowed to slay and plunder at their pleasure. Of the captives taken, all belonging to the five provinces across the Tigris, claimed as his own by Sapor, though ceded to Rome by his grandfather, were massacred in cold blood. The Count Elian, and the commanders of the legions who had conducted the gallant defence, were barbarously crucified. Many other Romans of high rank were subjected to the indignity of being manacled, and were dragged into Persia as slaves rather than as prisoners.
The campaign of A.D. 359 terminated with this dearly bought victory. The season was too far advanced for any fresh enterprise of importance; and Sapor was probably glad to give his army a rest after the toils and perils of the last three months. Accordingly he retired across the Tigris, without leaving (so far as appears) any garrisons in Mesopotamia, and began preparations for the campaign of A.D. 360. Stores of all kinds were accumulated during the winter; and, when the spring came, the indefatigable monarch once more invaded the enemy's country, pouring into Mesopotamia an army even more numerous and better appointed than that which he had led against Amida in the preceding year. His first object now was to capture Singara, a town of some consequence, which was, however, defended by only two Roman legions and a certain number of native soldiers. After a vain attempt to persuade the garrison to a surrender, the attack was made in the usual way, chiefly by scaling parties with ladders, and by battering parties which shook the walls with the ram. The defenders kept the sealers at bay by a constant discharge of stones and darts from their artillery, arrows from their bows, and leaden bullets from their slings. They met the assaults of the ram by attempts to fire the wooden covering which protected it and those who worked it. For some days these efforts sufficed; but after a while the besiegers found a weak point in the defences of the place—a tower so recently built that the mortar in which the stones were laid was still moist, and which consequently crumbled rapidly before the blows of a strong and heavy battering-ram, and in a short time fell to the ground. The Persians poured in through the gap, and were at once masters of the entire town, which ceased to resist after the catastrophe. This easy victory allowed Sapor to exhibit the better side of his character; he forbade the further shedding of blood, and ordered that as many as possible of the garrisons and citizens should be taken alive. Reviving a favorite policy of Oriental rulers from very remote times, he transported these captives to the extreme eastern parts of his empire, where they might be of the greatest service to him in defending his frontier against the Scythians and Indians.
It is not really surprising, though the historian of the war regards it as needing explanation, that no attempt was made to relieve Singara by the Romans. The siege was short; the place was considered strong; the nearest point held by a powerful Roman force was Nisibis, which was at least sixty miles distant from Singara. The neighborhood of Singara was, moreover, ill supplied with water; and a relieving army would probably have soon found itself in difficulties. Singara, on the verge of the desert, was always perilously situated. Rome valued it as an outpost from which her enemy might be watched, and which might advertise her of a sudden danger, but could not venture to undertake its defence in case of an attack in force, and was prepared to hear of its capture with equanimity.
From Singara Sapor directed his march almost due northwards, and, leaving Nisibis unassailed upon his left, proceeded to attack the strong fort known indifferently as Phoenica or Bezabde. This was a position on the east bank of the Tigris, near the point where that river quits the mountains and debouches upon the plain; though not on the site, it may be considered the representative of the modern Jezireh, which commands the passes from the low country into the Kurdish mountains. Bezabde was the chief city of the province, called after it Zabdicene, one of the five ceded by Narses and greatly coveted by his grandson. It was much valued by Rome, was fortified in places with a double wall, and was guarded by three legions and a large body of Kurdish archers. Sapor, having reconnoitred the place, and, with his usual hardihood, exposed himself to danger in doing so, sent a flag of truce to demand a surrender, joining with the messengers some prisoners of high rank taken at Singara, lest the enemy should open fire upon his envoys. The device was successful; but the garrison proved stanch, and determined on resisting to the last. Once more all the known resources of attack and defence were brought into play; and after a long siege, of which the most important incident was an attempt made by the bishop of the place to induce Sapor to withdraw, the wall was at last breached, the city taken, and its defenders indiscriminately massacred. Regarding the position as one of first-rate importance, Sapor, who had destroyed Singara, carefully repaired the defences of Bezabde, provisioned it abundantly, and garrisoned it with some of his best troops. He was well aware that the Romans would feel keenly the loss of so important a post, and expected that it would not be long before they made an effort to recover possession of it.
The winter was now approaching, but the Persian monarch still kept the field. The capture of Bezabde was followed by that of many other less important strongholds, which offered little resistance. At last, towards the close of the year, an attack was made upon a place called Virta, said to have been a fortress of great strength, and by some moderns identified with Tekrit, an important city upon the Tigris between Mosul and Bagdad. Here the career of the conqueror was at last arrested. Persuasion and force proved alike unavailing to induce or compel a surrender; and, after wasting the small remainder of the year, and suffering considerable loss, the Persian monarch reluctantly gave up the siege, and returned to his own country.
Meanwhile the movements of the Roman emperor had been slow and uncertain. Distracted between a jealous fear of his cousin Julian's proceedings in the West, and a desire of checking the advance of his rival Sapor in the East, he had left Constantinople in the early spring, but had journeyed leisurely through Cappadocia and Armenia Minor to Samosata, whence, after crossing the Euphrates, he had proceeded to Edessa, and there fixed himself. While in Cappadocia he had summoned to his presence Arsaces, the tributary king of Armenia, had reminded him of his engagements, and had endeavored to quicken his gratitude by bestowing on him liberal presents. At Edessa he employed himself during the whole of the summer in collecting troops and stores; nor was it till the autumnal equinox was past that he took the field, and, after weeping over the smoking ruins of Amida, marched to Bezabde, and, when the defenders rejected his overtures of peace, formed the siege of the place. Sapor was, we must suppose, now engaged before Virta, and it is probable that he thought Bezabde strong enough to defend itself. At any rate, he made no effort to afford it any relief; and the Roman emperor was allowed to employ all the resources at his disposal in reiterated assaults upon the walls. The defence, however, proved stronger than the attack. Time after time the bold sallies of the besieged destroyed the Roman works. At last the rainy season set in, and the low ground outside the town became a glutinous and adhesive marsh. It was no longer possible to continue the siege; and the disappointed emperor reluctantly drew off his troops, recrossed the Euphrates, and retired into winter quarters at Antioch.
The successes of Sapor in the campaigns of A.D. 359 and 360, his captures of Amida, Singara, and Bezabde, together with the unfortunate issue of the expedition made by Constantius against the last-named place, had a tendency to shake the fidelity of the Roman vassal-kings, Arsaces of Armenia, and Meribanes of Iberia. Constantius, therefore, during the winter of A.D. 360-1, which he passed at Antioch, sent emissaries to the courts of these monarchs, and endeavored to secure their fidelity by loading them with costly presents. His policy seems to have been so far successful that no revolt of these kingdoms took place; they did not as yet desert the Romans or make their submission to Sapor. Their monarchs seem to have simply watched events, prepared to declare themselves distinctly on the winning side so soon as fortune should incline unmistakably to one or the other combatant. Meanwhile they maintained the fiction of a nominal dependence upon Rome.
It might have been expected that the year A.D. 361 would have been a turning-point in the war, and that, if Rome did not by a great effort assert herself and recover her prestige, the advance of Persia would have been marked and rapid. But the actual course of events was far different. Hesitation and diffidence characterize the movements of both parties to the contest, and the year is signalized by no important enterprise on the part of either monarch. Constantius reoccupied Edessa, and had (we are told) some thoughts of renewing the siege of Bezabde; actually, however, he did not advance further, but contented himself with sending a part of his army to watch Sapor, giving them strict orders not to risk an engagement. Sapor, on his side, began the year with demonstrations which were taken to mean that he was about to pass the Euphrates; but in reality he never even brought his troops across the Tigris, or once set foot in Mesopotamia. After wasting weeks or months in a futile display of his armed strength upon the eastern bank of the river, and violently alarming the officers sent by Constantius to observe his movements, he suddenly, towards autumn, withdrew his troops, having attempted nothing, and quietly returned to his capital! It is by no means difficult to understand the motives which actuated Constantius. He was, month after month, receiving intelligence from the West of steps taken by Julian which amounted to open rebellion, and challenged him to engage in civil war. So long as Sapor threatened invasion he did not like to quit Mesopotamia, lest he might appear to have sacrificed the interests of his country to his own private quarrels; but he must have been anxious to return to the seat of empire from the first moment that intelligence reached him of Julian's assumption of the imperial name and dignity; and when Sapor's retreat was announced he naturally made all haste to reach his capital. Meanwhile the desire of keeping his army intact caused him to refrain from any movement which involved the slightest risk of bringing on a battle, and, in fact, reduced him to inaction. So much is readily intelligible. But what at this time withheld Sapor, when he had so grand an opportunity of making an impression upon Rome—what paralyzed his arm when it might have struck with such effect it is far from easy to understand, though perhaps not impossible to conjecture. The historian of the war ascribes his abstinence to a religious motive, telling us that the auguries were not favorable for the Persians crossing the Tigris. But there is no other evidence that the Persians of this period were the slaves of any such superstition as that noted by Ammianus, nor any probability that a monarch of Sapor's force of character would have suffered his military policy to be affected by omens. We must therefore ascribe the conduct of the Persian king to some cause not recorded by the historian—same failure of health, or some peril from internal or external enemies which called him away from the scene of his recent exploits, just at the time when his continued presence there was most important. Once before in his lifetime, an invasion of his eastern provinces had required his immediate presence, and allowed his adversary to quit Mesopotamia and march against Magnentius. It is not improbable that a fresh attack of the same or some other barbarians now again happened opportunely for the Romans, calling Sapor away, and thus enabling Constantius to turn his hack upon the East, and set out for Europe in order to meet Julian.
The meeting, however, was not destined to take place. On his way from Antioch to Constantinople the unfortunate Constantius, anxious and perhaps over-fatigued, fell sick at Mopsucrene, in Cilicia, and died there, after a short illness, towards the close of A.D. 361. Julian the Apostate succeeded peacefully to the empire whereto he was about to assert his right by force of arms; and Sapor found that the war which he had provoked with Rome, in reliance upon his adversary's weakness and incapacity, had to be carried on with a prince of far greater natural powers and of much superior military training.