The strength of Aurelian had crushed on every side the enemies of Rome. After his death they seemed to revive with an increase of fury and of numbers. They were again vanquished by the active vigor of Probus, who, in a short reign of about six years, equalled the fame of ancient heroes, and restored peace and order to every province of the Roman world. The dangerous frontier of Rhætia he so firmly secured, that he left it without the suspicion of an enemy. He broke the wandering power of the Sarmatian tribes, and by the terror of his arms compelled those barbarians to relinquish their spoil. The Gothic nation courted the alliance of so warlike an emperor. He attacked the Isaurians in their mountains, besieged and took several of their strongest castles, and flattered himself that he had forever suppressed a domestic foe, whose independence so deeply wounded the majesty of the empire. The troubles excited by the usurper Firmus in the Upper Egypt had never been perfectly appeased, and the cities of Ptolemais and Coptos, fortified by the alliance of the Blemmyes, still maintained an obscure rebellion. The chastisement of those cities, and of their auxiliaries the savages of the South, is said to have alarmed the court of Persia, and the Great King sued in vain for the friendship of Probus. Most of the exploits which distinguished his reign were achieved by the personal valor and conduct of the emperor, insomuch that the writer of his life expresses some amazement how, in so short a time, a single man could be present in so many distant wars. The remaining actions he intrusted to the care of his lieutenants, the judicious choice of whom forms no inconsiderable part of his glory. Carus, Diocletian, Maximian, Constantius, Galerius, Asclepiodatus, Annibalianus, and a crowd of other chiefs, who afterwards ascended or supported the throne, were trained to arms in the severe school of Aurelian and Probus.
But the most important service which Probus rendered to the republic was the deliverance of Gaul, and the recovery of seventy flourishing cities oppressed by the barbarians of Germany, who, since the death of Aurelian, had ravaged that great province with impunity. Among the various multitude of those fierce invaders we may distinguish, with some degree of clearness, three great armies, or rather nations, successively vanquished by the valor of Probus. He drove back the Franks into their morasses; a descriptive circumstance from whence we may infer, that the confederacy known by the manly appellation of Free, already occupied the flat maritime country, intersected and almost overflown by the stagnating waters of the Rhine, and that several tribes of the Frisians and Batavians had acceded to their alliance. He vanquished the Burgundians, a considerable people of the Vandalic race. * They had wandered in quest of booty from the banks of the Oder to those of the Seine. They esteemed themselves sufficiently fortunate to purchase, by the restitution of all their booty, the permission of an undisturbed retreat. They attempted to elude that article of the treaty. Their punishment was immediate and terrible. But of all the invaders of Gaul, the most formidable were the Lygians, a distant people, who reigned over a wide domain on the frontiers of Poland and Silesia. In the Lygian nation, the Arii held the first rank by their numbers and fierceness. "The Arii" (it is thus that they are described by the energy of Tacitus) "study to improve by art and circumstances the innate terrors of their barbarism. Their shields are black, their bodies are painted black. They choose for the combat the darkest hour of the night. Their host advances, covered as it were with a funeral shade; nor do they often find an enemy capable of sustaining so strange and infernal an aspect. Of all our senses, the eyes are the first vanquished in battle." Yet the arms and discipline of the Romans easily discomfited these horrid phantoms. The Lygii were defeated in a general engagement, and Semno, the most renowned of their chiefs, fell alive into the hands of Probus. That prudent emperor, unwilling to reduce a brave people to despair, granted them an honorable capitulation, and permitted them to return in safety to their native country. But the losses which they suffered in the march, the battle, and the retreat, broke the power of the nation: nor is the Lygian name ever repeated in the history either of Germany or of the empire. The deliverance of Gaul is reported to have cost the lives of four hundred thousand of the invaders; a work of labor to the Romans, and of expense to the emperor, who gave a piece of gold for the head of every barbarian. But as the fame of warriors is built on the destruction of human kind, we may naturally suspect, that the sanguinary account was multiplied by the avarice of the soldiers, and accepted without any very severe examination by the liberal vanity of Probus.
Since the expedition of Maximin, the Roman generals had confined their ambition to a defensive war against the nations of Germany, who perpetually pressed on the frontiers of the empire. The more daring Probus pursued his Gallic victories, passed the Rhine, and displayed his invincible eagles on the banks of the Elbe and the Necker. He was fully convinced that nothing could reconcile the minds of the barbarians to peace, unless they experienced, in their own country, the calamities of war. Germany, exhausted by the ill success of the last emigration, was astonished by his presence. Nine of the most considerable princes repaired to his camp, and fell prostrate at his feet. Such a treaty was humbly received by the Germans, as it pleased the conqueror to dictate. He exacted a strict restitution of the effects and captives which they had carried away from the provinces; and obliged their own magistrates to punish the more obstinate robbers who presumed to detain any part of the spoil. A considerable tribute of corn, cattle, and horses, the only wealth of barbarians, was reserved for the use of the garrisons which Probus established on the limits of their territory. He even entertained some thoughts of compelling the Germans to relinquish the exercise of arms, and to trust their differences to the justice, their safety to the power, of Rome. To accomplish these salutary ends, the constant residence of an Imperial governor, supported by a numerous army, was indispensably requisite. Probus therefore judged it more expedient to defer the execution of so great a design; which was indeed rather of specious than solid utility. Had Germany been reduced into the state of a province, the Romans, with immense labor and expense, would have acquired only a more extensive boundary to defend against the fiercer and more active barbarians of Scythia.
Instead of reducing the warlike natives of Germany to the condition of subjects, Probus contented himself with the humble expedient of raising a bulwark against their inroads. The country which now forms the circle of Swabia had been left desert in the age of Augustus by the emigration of its ancient inhabitants. The fertility of the soil soon attracted a new colony from the adjacent provinces of Gaul. Crowds of adventurers, of a roving temper and of desperate fortunes, occupied the doubtful possession, and acknowledged, by the payment of tithes the majesty of the empire. To protect these new subjects, a line of frontier garrisons was gradually extended from the Rhine to the Danube. About the reign of Hadrian, when that mode of defence began to be practised, these garrisons were connected and covered by a strong intrenchment of trees and palisades. In the place of so rude a bulwark, the emperor Probus constructed a stone wall of a considerable height, and strengthened it by towers at convenient distances. From the neighborhood of Newstadt and Ratisbon on the Danube, it stretched across hills, valleys, rivers, and morasses, as far as Wimpfen on the Necker, and at length terminated on the banks of the Rhine, after a winding course of near two hundred miles. This important barrier, uniting the two mighty streams that protected the provinces of Europe, seemed to fill up the vacant space through which the barbarians, and particularly the Alemanni, could penetrate with the greatest facility into the heart of the empire. But the experience of the world, from China to Britain, has exposed the vain attempt of fortifying any extensive tract of country. An active enemy, who can select and vary his points of attack, must, in the end, discover some feeble spot, on some unguarded moment. The strength, as well as the attention, of the defenders is divided; and such are the blind effects of terror on the firmest troops, that a line broken in a single place is almost instantly deserted. The fate of the wall which Probus erected may confirm the general observation. Within a few years after his death, it was overthrown by the Alemanni. Its scattered ruins, universally ascribed to the power of the Dæmon, now serve only to excite the wonder of the Swabian peasant.
Among the useful conditions of peace imposed by Probus on the vanquished nations of Germany, was the obligation of supplying the Roman army with sixteen thousand recruits, the bravest and most robust of their youth. The emperor dispersed them through all the provinces, and distributed this dangerous reenforcement, in small bands of fifty or sixty each, among the national troops; judiciously observing, that the aid which the republic derived from the barbarians should be felt but not seen. Their aid was now become necessary. The feeble elegance of Italy and the internal provinces could no longer support the weight of arms. The hardy frontiers of the Rhine and Danube still produced minds and bodies equal to the labors of the camp; but a perpetual series of wars had gradually diminished their numbers. The infrequency of marriage, and the ruin of agriculture, affected the principles of population, and not only destroyed the strength of the present, but intercepted the hope of future, generations. The wisdom of Probus embraced a great and beneficial plan of replenishing the exhausted frontiers, by new colonies of captive or fugitive barbarians, on whom he bestowed lands, cattle, instruments of husbandry, and every encouragement that might engage them to educate a race of soldiers for the service of the republic. Into Britain, and most probably into Cambridgeshire, he transported a considerable body of Vandals. The impossibility of an escape reconciled them to their situation, and in the subsequent troubles of that island, they approved themselves the most faithful servants of the state. Great numbers of Franks and Gepidæ were settled on the banks of the Danube and the Rhine. A hundred thousand Bastarnæ, expelled from their own country, cheerfully accepted an establishment in Thrace, and soon imbibed the manners and sentiments of Roman subjects. But the expectations of Probus were too often disappointed. The impatience and idleness of the barbarians could ill brook the slow labors of agriculture. Their unconquerable love of freedom, rising against despotism, provoked them into hasty rebellions, alike fatal to themselves and to the provinces; nor could these artificial supplies, however repeated by succeeding emperors, restore the important limit of Gaul and Illyricum to its ancient and native vigor.
Of all the barbarians who abandoned their new settlements, and disturbed the public tranquillity, a very small number returned to their own country. For a short season they might wander in arms through the empire; but in the end they were surely destroyed by the power of a warlike emperor. The successful rashness of a party of Franks was attended, however, with such memorable consequences, that it ought not to be passed unnoticed. They had been established by Probus, on the sea-coast of Pontus, with a view of strengthening the frontier against the inroads of the Alani. A fleet stationed in one of the harbors of the Euxine fell into the hands of the Franks; and they resolved, through unknown seas, to explore their way from the mouth of the Phasis to that of the Rhine. They easily escaped through the Bosphorus and the Hellespont, and cruising along the Mediterranean, indulged their appetite for revenge and plunder by frequent descents on the unsuspecting shores of Asia, Greece, and Africa. The opulent city of Syracuse, in whose port the natives of Athens and Carthage had formerly been sunk, was sacked by a handful of barbarians, who massacred the greatest part of the trembling inhabitants. From the Island of Sicily, the Franks proceeded to the columns of Hercules, trusted themselves to the ocean, coasted round Spain and Gaul, and steering their triumphant course through the British Channel, at length finished their surprising voyage, by landing in safety on the Batavian or Frisian shores. The example of their success, instructing their countrymen to conceive the advantages and to despise the dangers of the sea, pointed out to their enterprising spirit a new road to wealth and glory.
Notwithstanding the vigilance and activity of Probus, it was almost impossible that he could at once contain in obedience every part of his wide-extended dominions. The barbarians, who broke their chains, had seized the favorable opportunity of a domestic war. When the emperor marched to the relief of Gaul, he devolved the command of the East on Saturninus. That general, a man of merit and experience, was driven into rebellion by the absence of his sovereign, the levity of the Alexandrian people, the pressing instances of his friends, and his own fears; but from the moment of his elevation, he never entertained a hope of empire, or even of life. "Alas!" he said, "the republic has lost a useful servant, and the rashness of an hour has destroyed the services of many years. You know not," continued he, "the misery of sovereign power; a sword is perpetually suspended over our head. We dread our very guards, we distrust our companions. The choice of action or of repose is no longer in our disposition, nor is there any age, or character, or conduct, that can protect us from the censure of envy. In thus exalting me to the throne, you have doomed me to a life of cares, and to an untimely fate. The only consolation which remains is, the assurance that I shall not fall alone." But as the former part of his prediction was verified by the victory, so the latter was disappointed by the clemency of Probus. That amiable prince attempted even to save the unhappy Saturninus from the fury of the soldiers. He had more than once solicited the usurper himself to place some confidence in the mercy of a sovereign who so highly esteemed his character, that he had punished, as a malicious informer, the first who related the improbable news of his disaffection. Saturninus might, perhaps, have embraced the generous offer, had he not been restrained by the obstinate distrust of his adherents. Their guilt was deeper, and their hopes more sanguine, than those of their experienced leader.
The revolt of Saturninus was scarcely extinguished in the East, before new troubles were excited in the West, by the rebellion of Bonosus and Proculus, in Gaul. The most distinguished merit of those two officers was their respective prowess, of the one in the combats of Bacchus, of the other in those of Venus, yet neither of them was destitute of courage and capacity, and both sustained, with honor, the august character which the fear of punishment had engaged them to assume, till they sunk at length beneath the superior genius of Probus. He used the victory with his accustomed moderation, and spared the fortune, as well as the lives of their innocent families.
The arms of Probus had now suppressed all the foreign and domestic enemies of the state. His mild but steady administration confirmed the reestablishment of the public tranquillity; nor was there left in the provinces a hostile barbarian, a tyrant, or even a robber, to revive the memory of past disorders. It was time that the emperor should revisit Rome, and celebrate his own glory and the general happiness. The triumph due to the valor of Probus was conducted with a magnificence suitable to his fortune, and the people who had so lately admired the trophies of Aurelian, gazed with equal pleasure on those of his heroic successor. We cannot, on this occasion, forget the desperate courage of about fourscore gladiators, reserved, with near six hundred others, for the inhuman sports of the amphitheatre. Disdaining to shed their blood for the amusement of the populace, they killed their keepers, broke from the place of their confinement, and filled the streets of Rome with blood and confusion. After an obstinate resistance, they were overpowered and cut in pieces by the regular forces; but they obtained at least an honorable death, and the satisfaction of a just revenge.
The military discipline which reigned in the camps of Probus was less cruel than that of Aurelian, but it was equally rigid and exact. The latter had punished the irregularities of the soldiers with unrelenting severity, the former prevented them by employing the legions in constant and useful labors. When Probus commanded in Egypt, he executed many considerable works for the splendor and benefit of that rich country. The navigation of the Nile, so important to Rome itself, was improved; and temples, buildings, porticos, and palaces were constructed by the hands of the soldiers, who acted by turns as architects, as engineers, and as husbandmen. It was reported of Hannibal, that in order to preserve his troops from the dangerous temptations of idleness, he had obliged them to form large plantations of olive-trees along the coast of Africa. From a similar principle, Probus exercised his legions in covering with rich vineyards the hills of Gaul and Pannonia, and two considerable spots are described, which were entirely dug and planted by military labor. One of these, known under the name of Mount Almo, was situated near Sirmium, the country where Probus was born, for which he ever retained a partial affection, and whose gratitude he endeavored to secure, by converting into tillage a large and unhealthy tract of marshy ground. An army thus employed constituted perhaps the most useful, as well as the bravest, portion of Roman subjects.
But in the prosecution of a favorite scheme, the best of men, satisfied with the rectitude of their intentions, are subject to forget the bounds of moderation; nor did Probus himself sufficiently consult the patience and disposition of his fierce legionaries. The dangers of the military profession seem only to be compensated by a life of pleasure and idleness; but if the duties of the soldier are incessantly aggravated by the labors of the peasant, he will at last sink under the intolerable burden, or shake it off with indignation. The imprudence of Probus is said to have inflamed the discontent of his troops. More attentive to the interests of mankind than to those of the army, he expressed the vain hope, that, by the establishment of universal peace, he should soon abolish the necessity of a standing and mercenary force. The unguarded expression proved fatal to him. In one of the hottest days of summer, as he severely urged the unwholesome labor of draining the marshes of Sirmium, the soldiers, impatient of fatigue, on a sudden threw down their tools, grasped their arms, and broke out into a furious mutiny. The emperor, conscious of his danger, took refuge in a lofty tower, constructed for the purpose of surveying the progress of the work. The tower was instantly forced, and a thousand swords were plunged at once into the bosom of the unfortunate Probus. The rage of the troops subsided as soon as it had been gratified. They then lamented their fatal rashness, forgot the severity of the emperor, whom they had massacred, and hastened to perpetuate, by an honorable monument, the memory of his virtues and victories.
When the legions had indulged their grief and repentance for the death of Probus, their unanimous consent declared Carus, his Prætorian præfect, the most deserving of the Imperial throne. Every circumstance that relates to this prince appears of a mixed and doubtful nature. He gloried in the title of Roman Citizen; and affected to compare the purity of his blood with the foreign and even barbarous origin of the preceding emperors; yet the most inquisitive of his contemporaries, very far from admitting his claim, have variously deduced his own birth, or that of his parents, from Illyricum, from Gaul, or from Africa. Though a soldier, he had received a learned education; though a senator, he was invested with the first dignity of the army; and in an age when the civil and military professions began to be irrecoverably separated from each other, they were united in the person of Carus. Notwithstanding the severe justice which he exercised against the assassins of Probus, to whose favor and esteem he was highly indebted, he could not escape the suspicion of being accessory to a deed from whence he derived the principal advantage. He enjoyed, at least, before his elevation, an acknowledged character of virtue and abilities; but his austere temper insensibly degenerated into moroseness and cruelty; and the imperfect writers of his life almost hesitate whether they shall not rank him in the number of Roman tyrants. When Carus assumed the purple, he was about sixty years of age, and his two sons, Carinus and Numerian had already attained the season of manhood.
The authority of the senate expired with Probus; nor was the repentance of the soldiers displayed by the same dutiful regard for the civil power, which they had testified after the unfortunate death of Aurelian. The election of Carus was decided without expecting the approbation of the senate, and the new emperor contented himself with announcing, in a cold and stately epistle, that he had ascended the vacant throne. A behavior so very opposite to that of his amiable predecessor afforded no favorable presage of the new reign: and the Romans, deprived of power and freedom, asserted their privilege of licentious murmurs. The voice of congratulation and flattery was not, however, silent; and we may still peruse, with pleasure and contempt, an eclogue, which was composed on the accession of the emperor Carus. Two shepherds, avoiding the noontide heat, retire into the cave of Faunus. On a spreading beech they discover some recent characters. The rural deity had described, in prophetic verses, the felicity promised to the empire under the reign of so great a prince. Faunus hails the approach of that hero, who, receiving on his shoulders the sinking weight of the Roman world, shall extinguish war and faction, and once again restore the innocence and security of the golden age.
It is more than probable, that these elegant trifles never reached the ears of a veteran general, who, with the consent of the legions, was preparing to execute the long-suspended design of the Persian war. Before his departure for this distant expedition, Carus conferred on his two sons, Carinus and Numerian, the title of Cæsar, and investing the former with almost an equal share of the Imperial power, directed the young prince, first to suppress some troubles which had arisen in Gaul, and afterwards to fix the seat of his residence at Rome, and to assume the government of the Western provinces. The safety of Illyricum was confirmed by a memorable defeat of the Sarmatians; sixteen thousand of those barbarians remained on the field of battle, and the number of captives amounted to twenty thousand. The old emperor, animated with the fame and prospect of victory, pursued his march, in the midst of winter, through the countries of Thrace and Asia Minor, and at length, with his younger son, Numerian, arrived on the confines of the Persian monarchy. There, encamping on the summit of a lofty mountain, he pointed out to his troops the opulence and luxury of the enemy whom they were about to invade.
The successor of Artaxerxes, * Varanes, or Bahram, though he had subdued the Segestans, one of the most warlike nations of Upper Asia, was alarmed at the approach of the Romans, and endeavored to retard their progress by a negotiation of peace. His ambassadors entered the camp about sunset, at the time when the troops were satisfying their hunger with a frugal repast. The Persians expressed their desire of being introduced to the presence of the Roman emperor. They were at length conducted to a soldier, who was seated on the grass. A piece of stale bacon and a few hard peas composed his supper. A coarse woollen garment of purple was the only circumstance that announced his dignity. The conference was conducted with the same disregard of courtly elegance. Carus, taking off a cap which he wore to conceal his baldness, assured the ambassadors, that, unless their master acknowledged the superiority of Rome, he would speedily render Persia as naked of trees as his own head was destitute of hair. Notwithstanding some traces of art and preparation, we may discover in this scene the manners of Carus, and the severe simplicity which the martial princes, who succeeded Gallienus, had already restored in the Roman camps. The ministers of the Great King trembled and retired.
The threats of Carus were not without effect. He ravaged Mesopotamia, cut in pieces whatever opposed his passage, made himself master of the great cities of Seleucia and Ctesiphon, (which seemed to have surrendered without resistance,) and carried his victorious arms beyond the Tigris. He had seized the favorable moment for an invasion. The Persian councils were distracted by domestic factions, and the greater part of their forces were detained on the frontiers of India. Rome and the East received with transports the news of such important advantages. Flattery and hope painted, in the most lively colors, the fall of Persia, the conquest of Arabia, the submission of Egypt, and a lasting deliverance from the inroads of the Scythian nations. But the reign of Carus was destined to expose the vanity of predictions. They were scarcely uttered before they were contradicted by his death; an event attended with such ambiguous circumstances, that it may be related in a letter from his own secretary to the præfect of the city. "Carus," says he, "our dearest emperor, was confined by sickness to his bed, when a furious tempest arose in the camp. The darkness which overspread the sky was so thick, that we could no longer distinguish each other; and the incessant flashes of lightning took from us the knowledge of all that passed in the general confusion. Immediately after the most violent clap of thunder, we heard a sudden cry that the emperor was dead; and it soon appeared, that his chamberlains, in a rage of grief, had set fire to the royal pavilion; a circumstance which gave rise to the report that Carus was killed by lightning. But, as far as we have been able to investigate the truth, his death was the natural effect of his disorder."