While the East anxiously expected the decision of this great contest, the emperor Diocletian, having assembled in Syria a strong army of observation, displayed from a distance the resources of the Roman power, and reserved himself for any future emergency of the war. On the intelligence of the victory he condescended to advance towards the frontier, with a view of moderating, by his presence and counsels, the pride of Galerius. The interview of the Roman princes at Nisibis was accompanied with every expression of respect on one side, and of esteem on the other. It was in that city that they soon afterwards gave audience to the ambassador of the Great King. The power, or at least the spirit, of Narses, had been broken by his last defeat; and he considered an immediate peace as the only means that could stop the progress of the Roman arms. He despatched Apharban, a servant who possessed his favor and confidence, with a commission to negotiate a treaty, or rather to receive whatever conditions the conqueror should impose. Apharban opened the conference by expressing his master's gratitude for the generous treatment of his family, and by soliciting the liberty of those illustrious captives. He celebrated the valor of Galerius, without degrading the reputation of Narses, and thought it no dishonor to confess the superiority of the victorious Cæsar, over a monarch who had surpassed in glory all the princes of his race. Notwithstanding the justice of the Persian cause, he was empowered to submit the present differences to the decision of the emperors themselves; convinced as he was, that, in the midst of prosperity, they would not be unmindful of the vicissitudes of fortune. Apharban concluded his discourse in the style of eastern allegory, by observing that the Roman and Persian monarchies were the two eyes of the world, which would remain imperfect and mutilated if either of them should be put out.
"It well becomes the Persians," replied Galerius, with a transport of fury, which seemed to convulse his whole frame, "it well becomes the Persians to expatiate on the vicissitudes of fortune, and calmly to read us lectures on the virtues of moderation. Let them remember their own moderation, towards the unhappy Valerian. They vanquished him by fraud, they treated him with indignity. They detained him till the last moment of his life in shameful captivity, and after his death they exposed his body to perpetual ignominy." Softening, however, his tone, Galerius insinuated to the ambassador, that it had never been the practice of the Romans to trample on a prostrate enemy; and that, on this occasion, they should consult their own dignity rather than the Persian merit. He dismissed Apharban with a hope that Narses would soon be informed on what conditions he might obtain, from the clemency of the emperors, a lasting peace, and the restoration of his wives and children. In this conference we may discover the fierce passions of Galerius, as well as his deference to the superior wisdom and authority of Diocletian. The ambition of the former grasped at the conquest of the East, and had proposed to reduce Persia into the state of a province. The prudence of the latter, who adhered to the moderate policy of Augustus and the Antonines, embraced the favorable opportunity of terminating a successful war by an honorable and advantageous peace.
In pursuance of their promise, the emperors soon afterwards appointed Sicorius Probus, one of their secretaries, to acquaint the Persian court with their final resolution. As the minister of peace, he was received with every mark of politeness and friendship; but, under the pretence of allowing him the necessary repose after so long a journey, the audience of Probus was deferred from day to day; and he attended the slow motions of the king, till at length he was admitted to his presence, near the River Asprudus in Media. The secret motive of Narses, in this delay, had been to collect such a military force as might enable him, though sincerely desirous of peace, to negotiate with the greater weight and dignity. Three persons only assisted at this important conference, the minister Apharban, the præfect of the guards, and an officer who had commanded on the Armenian frontier. The first condition proposed by the ambassador is not at present of a very intelligible nature; that the city of Nisibis might be established for the place of mutual exchange, or, as we should formerly have termed it, for the staple of trade, between the two empires. There is no difficulty in conceiving the intention of the Roman princes to improve their revenue by some restraints upon commerce; but as Nisibis was situated within their own dominions, and as they were masters both of the imports and exports, it should seem that such restraints were the objects of an internal law, rather than of a foreign treaty. To render them more effectual, some stipulations were probably required on the side of the king of Persia, which appeared so very repugnant either to his interest or to his dignity, that Narses could not be persuaded to subscribe them. As this was the only article to which he refused his consent, it was no longer insisted on; and the emperors either suffered the trade to flow in its natural channels, or contented themselves with such restrictions, as it depended on their own authority to establish.
As soon as this difficulty was removed, a solemn peace was concluded and ratified between the two nations. The conditions of a treaty so glorious to the empire, and so necessary to Persia Persian, may deserve a more peculiar attention, as the history of Rome presents very few transactions of a similar nature; most of her wars having either been terminated by absolute conquest, or waged against barbarians ignorant of the use of letters. I. The Aboras, or, as it is called by Xenophon, the Araxes, was fixed as the boundary between the two monarchies. That river, which rose near the Tigris, was increased, a few miles below Nisibis, by the little stream of the Mygdonius, passed under the walls of Singara, and fell into the Euphrates at Circesium, a frontier town, which, by the care of Diocletian, was very strongly fortified. Mesopotomia, the object of so many wars, was ceded to the empire; and the Persians, by this treaty, renounced all pretensions to that great province. II. They relinquished to the Romans five provinces beyond the Tigris. Their situation formed a very useful barrier, and their natural strength was soon improved by art and military skill. Four of these, to the north of the river, were districts of obscure fame and inconsiderable extent; Intiline, Zabdicene, Arzanene, and Moxoene; but on the east of the Tigris, the empire acquired the large and mountainous territory of Carduene, the ancient seat of the Carduchians, who preserved for many ages their manly freedom in the heart of the despotic monarchies of Asia. The ten thousand Greeks traversed their country, after a painful march, or rather engagement, of seven days; and it is confessed by their leader, in his incomparable relation of the retreat, that they suffered more from the arrows of the Carduchians, than from the power of the Great King. Their posterity, the Curds, with very little alteration either of name or manners, * acknowledged the nominal sovereignty of the Turkish sultan. III. It is almost needless to observe, that Tiridates, the faithful ally of Rome, was restored to the throne of his fathers, and that the rights of the Imperial supremacy were fully asserted and secured. The limits of Armenia were extended as far as the fortress of Sintha in Media, and this increase of dominion was not so much an act of liberality as of justice. Of the provinces already mentioned beyond the Tigris, the four first had been dismembered by the Parthians from the crown of Armenia; and when the Romans acquired the possession of them, they stipulated, at the expense of the usurpers, an ample compensation, which invested their ally with the extensive and fertile country of Atropatene. Its principal city, in the same situation perhaps as the modern Tauris, was frequently honored by the residence of Tiridates; and as it sometimes bore the name of Ecbatana, he imitated, in the buildings and fortifications, the splendid capital of the Medes.
The arduous work of rescuing the distressed empire from tyrants and barbarians had now been completely achieved by a succession of Illyrian peasants. As soon as Diocletian entered into the twentieth year of his reign, he celebrated that memorable æra, as well as the success of his arms, by the pomp of a Roman triumph. Maximian, the equal partner of his power, was his only companion in the glory of that day. The two Cæsars had fought and conquered, but the merit of their exploits was ascribed, according to the rigor of ancient maxims, to the auspicious influence of their fathers and emperors. The triumph of Diocletian and Maximian was less magnificent, perhaps, than those of Aurelian and Probus, but it was dignified by several circumstances of superior fame and good fortune. Africa and Britain, the Rhine, the Danube, and the Nile, furnished their respective trophies; but the most distinguished ornament was of a more singular nature, a Persian victory followed by an important conquest. The representations of rivers, mountains, and provinces, were carried before the Imperial car. The images of the captive wives, the sisters, and the children of the Great King, afforded a new and grateful spectacle to the vanity of the people. In the eyes of posterity, this triumph is remarkable, by a distinction of a less honorable kind. It was the last that Rome ever beheld. Soon after this period, the emperors ceased to vanquish, and Rome ceased to be the capital of the empire.
The spot on which Rome was founded had been consecrated by ancient ceremonies and imaginary miracles. The presence of some god, or the memory of some hero, seemed to animate every part of the city, and the empire of the world had been promised to the Capitol. The native Romans felt and confessed the power of this agreeable illusion. It was derived from their ancestors, had grown up with their earliest habits of life, and was protected, in some measure, by the opinion of political utility. The form and the seat of government were intimately blended together, nor was it esteemed possible to transport the one without destroying the other. But the sovereignty of the capital was gradually annihilated in the extent of conquest; the provinces rose to the same level, and the vanquished nations acquired the name and privileges, without imbibing the partial affections, of Romans. During a long period, however, the remains of the ancient constitution, and the influence of custom, preserved the dignity of Rome. The emperors, though perhaps of African or Illyrian extraction, respected their adopted country, as the seat of their power, and the centre of their extensive dominions. The emergencies of war very frequently required their presence on the frontiers; but Diocletian and Maximian were the first Roman princes who fixed, in time of peace, their ordinary residence in the provinces; and their conduct, however it might be suggested by private motives, was justified by very specious considerations of policy. The court of the emperor of the West was, for the most part, established at Milan, whose situation, at the foot of the Alps, appeared far more convenient than that of Rome, for the important purpose of watching the motions of the barbarians of Germany. Milan soon assumed the splendor of an Imperial city. The houses are described as numerous and well built; the manners of the people as polished and liberal. A circus, a theatre, a mint, a palace, baths, which bore the name of their founder Maximian; porticos adorned with statues, and a double circumference of walls, contributed to the beauty of the new capital; nor did it seem oppressed even by the proximity of Rome. To rival the majesty of Rome was the ambition likewise of Diocletian, who employed his leisure, and the wealth of the East, in the embellishment of Nicomedia, a city placed on the verge of Europe and Asia, almost at an equal distance between the Danube and the Euphrates. By the taste of the monarch, and at the expense of the people, Nicomedia acquired, in the space of a few years, a degree of magnificence which might appear to have required the labor of ages, and became inferior only to Rome, Alexandria, and Antioch, in extent of populousness. The life of Diocletian and Maximian was a life of action, and a considerable portion of it was spent in camps, or in the long and frequent marches; but whenever the public business allowed them any relaxation, they seemed to have retired with pleasure to their favorite residences of Nicomedia and Milan. Till Diocletian, in the twentieth year of his reign, celebrated his Roman triumph, it is extremely doubtful whether he ever visited the ancient capital of the empire. Even on that memorable occasion his stay did not exceed two months. Disgusted with the licentious familiarity of the people, he quitted Rome with precipitation thirteen days before it was expected that he should have appeared in the senate, invested with the ensigns of the consular dignity.
The dislike expressed by Diocletian towards Rome and Roman freedom, was not the effect of momentary caprice, but the result of the most artful policy. That crafty prince had framed a new system of Imperial government, which was afterwards completed by the family of Constantine; and as the image of the old constitution was religiously preserved in the senate, he resolved to deprive that order of its small remains of power and consideration. We may recollect, about eight years before the elevation, of Diocletian the transient greatness, and the ambitious hopes, of the Roman senate. As long as that enthusiasm prevailed, many of the nobles imprudently displayed their zeal in the cause of freedom; and after the successes of Probus had withdrawn their countenance from the republican party, the senators were unable to disguise their impotent resentment. As the sovereign of Italy, Maximian was intrusted with the care of extinguishing this troublesome, rather than dangerous spirit, and the task was perfectly suited to his cruel temper. The most illustrious members of the senate, whom Diocletian always affected to esteem, were involved, by his colleague, in the accusation of imaginary plots; and the possession of an elegant villa, or a well-cultivated estate, was interpreted as a convincing evidence of guilt. The camp of the Prætorians, which had so long oppressed, began to protect, the majesty of Rome; and as those haughty troops were conscious of the decline of their power, they were naturally disposed to unite their strength with the authority of the senate. By the prudent measures of Diocletian, the numbers of the Prætorians were insensibly reduced, their privileges abolished, and their place supplied by two faithful legions of Illyricum, who, under the new titles of Jovians and Herculians, were appointed to perform the service of the Imperial guards. But the most fatal though secret wound, which the senate received from the hands of Diocletian and Maximian, was inflicted by the inevitable operation of their absence. As long as the emperors resided at Rome, that assembly might be oppressed, but it could scarcely be neglected. The successors of Augustus exercised the power of dictating whatever laws their wisdom or caprice might suggest; but those laws were ratified by the sanction of the senate. The model of ancient freedom was preserved in its deliberations and decrees; and wise princes, who respected the prejudices of the Roman people, were in some measure obliged to assume the language and behavior suitable to the general and first magistrate of the republic. In the armies and in the provinces, they displayed the dignity of monarchs; and when they fixed their residence at a distance from the capital, they forever laid aside the dissimulation which Augustus had recommended to his successors. In the exercise of the legislative as well as the executive power, the sovereign advised with his ministers, instead of consulting the great council of the nation. The name of the senate was mentioned with honor till the last period of the empire; the vanity of its members was still flattered with honorary distinctions; but the assembly which had so long been the source, and so long the instrument of power, was respectfully suffered to sink into oblivion. The senate of Rome, losing all connection with the Imperial court and the actual constitution, was left a venerable but useless monument of antiquity on the Capitoline hill.