A northern pretender, Aureolus, having marched from Rhætia against Milan, Gallienus fell during the siege of this town, most likely by the hands of his own men. He was a curse to the Roman empire, and his death was its deliverance. After him came a great man, M. Aurelius Claudius, who received the well-earned name of Gothicus. This emperor had to face a new invasion of the Goths, who burst in by the Propontis, and once more destroyed Cyzicus. These now made their appearance in Macedon, besieged even Thessalonica, and from thence marched into the interior of the country. There they met with Claudius, and they wished to retreat back again to the Danube; but Claudius defeated them near Nissa, on the borders of Bulgaria and Servia, in a great battle in which they were all but annihilated. New hordes, however, were always pouring in, the East and West Goths being now joined by the Vandals; and Claudius, while going on with the war against them, died at Sirmium in the middle of his career, either of the plague or of an epidemic caused by the war. The seat of the disease seems to have been in Mœsia, where it did great havoc, both among the Romans and among the Goths. He was succeeded by Aurelian.

The victory of Claudius over the Goths had ensured the safety of the Roman empire, although he still left much undone. The empire of Palmyra evidently was friendly, and it protected the eastern frontier: with Tetricus, the relations were at least perfectly peaceful. Claudius himself had recommended Aurelian as the ablest of his generals, and the senate and the army swore allegiance to him. Aurelian did great things during the five years of his reign (until 273): he restored the empire. One might be tempted to apply to him the remarkable passage in Curtius;^[62] but it is not to be believed that such pure Latin should have still been written in his reign. Gibbon must have thought this less unlikely, as far at least as regards the time of Gordian, for which he decides; but the passage on Tyre,^[63] to have any meaning at all, must be referred to the times of Septimius Severus and Caracalla. Although Aurelian is no ideal of a character, yet there is much in his reign which gives one pleasure, like every age in which anything that has fallen into ruin has been restored. But unhappily there are also here no sufficient sources; all is obscure: the imperial history, on the whole, is much more so than that of the republic; we are much better able to reconstruct the history of the twelfth and thirteenth century from the chronicles. The accounts we have of Aurelian, although they may be strung together, form no history: the coins are far safer authorities for this time, and with these the statements of our wretched historians cannot be made to agree. Gibbon has done everything that was possible, nor will his work ever be surpassed.

Aurelian passed the five years of his reign in an activity which beggars belief, going from one frontier to another, and from war to war. At first, he wisely made peace with the Goths, to whom he gave up the claims of Rome on Dacia. This country may have been in a condition like that of Gaul in the fifth century. The Romans may have kept their ground only in the impassable places of Transylvania, which he now evacuated, there being no hope left of driving back the Goths who had made inroads almost everywhere. The population of Dacia had been so much weakened by the wars, that the country could not be kept: those who wished to leave it, now settled in Bulgaria which thereby gained strength.—The war against the great Zenobia, who was already dreaming of nothing less than an Asiatic empire, was decided by two battles, at Antioch and at Emesa. As Zenobia could stand her ground against the Persians, but not against the Roman legions, her infantry must have been bad: it may be that she had formed in Syria a militia which overawed the Persians, whereas the Romans, who did not wish to give arms into the hands of the borderers, carried on the war with the aid of mercenaries. Zenobia’s defence of Palmyra did not answer the expectation which was entertained of her courage; for she fled and was taken prisoner. In her captivity, she showed herself to be an Asiatic woman, by sacrificing her best advisers as having beguiled her into bad policy: among these was the ingenious Longinus. As without doubt, even at that time, there was in many minds the idea of a Greek Asiatic Empire, an intellectual Greek like Longinus may indeed have suggested such a thought to his princess. It was one of the acts which have stained Aurelian’s purple, that he had this distinguished man put to death; and still worse was his giving up Palmyra to destruction on account of a rebellion of its inhabitants.

Thus the East was again tranquillized, the peace with the Persians being secured until the times of Carus, as it seems, by treaties. Aurelian now returned to Europe to reunite the West with the empire; whereupon he was met by Tetricus, who felt that his own life was not safe among the mutinous soldiers, and wished to get himself out of this position: but the soldiers of Tetricus fought with such spirit in the neighbourhood of Chalons, that one may see how national was their cause, and how determined was the wish for separation. It is remarkable that the French historians have never understood nor discerned the national development of France, which always renewed itself from the time of Julius Cæsar; just as they also have ever overlooked the distinctly marked difference between the literature of Northern and Southern France. It cannot be accurately made out, whether it was now, or somewhat sooner or later, that the German tribes broke through the frontier. The Alemanni, Lombards (Juthungi), and Vandals—the first two at least—passed the Po and threatened Rome: they were defeated near Fano (Fanum Fortunæ), very nearly in the same neighbourhood where Hasdrubal fell in the second Punic War.

Aurelian, who could not live without war, was on the eve of renewing that against the Persians: but he was murdered while on his march, at the crafty instigation, it is said, of an infamous secretary whose fraud he had found out. This story, however, is perhaps one of the many tales which were devised to screen the guilt of the real perpetrators: another conspiracy had already been discovered once before. The army bewailed him, and determined that none of the leading men who had had a share in his murder should reap any advantage from it. This accounts for the strange demand which the army made to the senate, to appoint the successor of Aurelian. The senate mistrusted this, or it was afraid that the soldiers might repent; but the latter are said to have so steadfastly stood by their declaration, that the empire remained for eight months without an emperor, nor did any one arise in the provinces.

At last,—so we are told,—Tacitus, the princeps senatus, was elected, who was distinguished for everything that could at all distinguish a senator,—immense fortune, of which he made a good use; a blameless life; administrative skill; and in his youth, military valour. On his election, he gave the senate the promise that he would look upon himself as its servant; whereupon the senators already began to give themselves up to their daydreams of freedom and power. The emperor was now to be their first servant; all rule and might was to be in the hands of the senate, and the republic was to be restored:—in a word, they expected to be like the senate of Venice. But that dream lasted but a short time. Tacitus went to the army in Asia Minor. The statement of his advanced age rests on the authority of the latest Greeks, and deserves little credit: the earlier writers say nothing about it. How they could then have elected an old man in his seventy-sixth year, is scarcely to be understood, as they needed a military prince. This reminds us of the Roman Cardinals, who elect an aged Pope to have so much more the hope of succeeding him themselves. Although Tacitus carried on the war against the Alans with success, the Romans were not yet rid of their causes for uneasiness in that quarter. When he died at Tarsus, in all likelihood it was quietly in his bed, of illness or exhaustion: murder seems not to be thought of. After his death, the throne was usurped by his brother Quintilius,^[64] to whom however the legions refused obedience.

They proclaimed Probus emperor, who is the most excellent of the Cæsars of that age. Quite as great a general as Aurelian, he still at the same time turned his mind to the protection of the empire against foreign foes, and to raising it at home from the wretched condition into which it had fallen. He had many rebellions to put down, but he had especially to wage war against the Alans, the Franks, the Alemanni, and the Sarmatians. The Franks he drove back into the marshes of the Netherlands; and he not only defeated the Alemanni, but he also crossed the Rhine, and regained the Suabian empire: he is likewise said to have repaired the limes. We are told that he wanted to form Germany into a province, which at that time was much more feasible than it had been before: for the southern Germans had already become much nearer to the Romans in their manners. Had Diocletian given himself the same trouble, and established a Roman power in the south of Germany, he might perhaps have succeeded.—It would have been possible to collect the Germans into towns, and to accustom them to a regular city life, for in the reign of Valentinian, we find them afterwards on the banks of the Neckar already settled in larger villages and in fortified towns, and no longer in scattered cottages. Probus achieved an incredible number of great undertakings in every quarter, crossing the empire from one frontier to the other with the power and speed of lightning: rest, during the five years of his reign, he never once enjoyed; but, on the other hand, he was unspeakably beloved by his people. Once also he triumphed in Rome, as Aurelian had likewise done: yet his coins not only bear the legend, Invicto Imperatori Probo, but also Bono Imperatori Probo. The soldiers only became estranged from him, because he made their work too hard, as he exacted from them, besides all their military duty, task-service for the restoration of the provinces. Like Aurelian and Decius, he came from the neighbourhood of the Limes Illyricus, being perhaps descended from military settlers; and therefore he wished to revive tillage in the neighbourhood of Sermium, and to drain the fens. To this unwholesome labour he kept the soldiers, employing them in digging the drains. As he did not yield to any representations made to him, the soldiers can scarcely be blamed when in their despair they would bear the heavy yoke no longer. He was murdered in the year 282; yet they still wept over his loss.

After his death, they raised the præfectus prætorio Carus to the throne. Whether Carus was born at Rome, or in Illyricum, or at Narbonne, we do not know: in a letter which is still extant, he calls himself a Roman senator,—a proof that the senatus consultum in the reign of Gallienus, that no senator should be a general, must have been something different from what is generally believed, and even Gibbon thinks it to have been. Perhaps Gallienus only took away from the senators the government of the provinces with the imperium, so that this was put an end to altogether, except in the short time of the reign of Tacitus; but even then, he did not shut them out from every kind of military command. As Carus also was quite in his element when there was a war, he led his soldiers against the Persians with the most signal success; and this was the last war but one in which this was the case: he is said to have retaken Ctesiphon; but this cannot be positively asserted. However this may be, Persia had lost the power which she had in the days of Ardaschir; and the Persian king Bahram, who was paralysed by fear, was quite unable to make head against the Roman army. Carus penetrated very far beyond the Persian frontier. Here he is said to have been struck by lightning in his tent:—whether this be true, or whether he did not rather fall by the hands of assassins, we cannot make out for certain. The soldiers, however, could not be got to advance any further: the omen of the prætorium struck by lightning was too dreadful. Numerian the son of Carus, a well educated and well-bred young man, good-hearted but unwarlike, was in the camp; the other one, Carinus, had remained in Rome: the latter was another Commodus, being a profligate and a tyrant. Numerian died, and the præfectus prætorio, Arrius Aper, is said to have concealed his death to found his own dominion on it. But it was detected; and it was laid to the charge of Aper by the Illyrian Diocletian, who was backed by the favour of the army. Being the most distinguished of the generals, he put forth claims to the throne: as for Carinus, he had made himself so hateful by his profligacy, that the army would not hear of him. Diocletian stabbed Aper with his own hands. A female soothsayer had told him that he should ascend the throne, if he killed an aper; and therefore in all his hunts, he had tried to kill a wild boar. The oracle now came true. Carinus gathered together the legions of the west, and great battle in Mœsia decided the fate of the throne. For when Carinus was on the point of gaining the victory, he was stabbed by a man whom he had foully wronged; and the soldiers now acknowledged Diocletian, who had been all but beaten, as their emperor, 285.