It was possibly in this same year 210, at any rate during his stay in Britain, that Severus completed a great and necessary work—the repair of the wall of Hadrian. So grievously had this long barrier suffered at the hands of the barbarians that reconstruction seemed to the soldiers engaged in it like an actual fresh construction. It is only thus that we can explain the language of the careless, inaccurate authors of the Historia Augusta, who, forgetful apparently of the fact that they have already assigned the credit of the work to Hadrian, now say of Severus: “The greatest glory of his reign is that he fortified Britain by a wall drawn across the island and ending on both sides with the ocean, for which achievement he received the name of Britannicus”. Attempts have been made to explain the apparent discrepancy between the two accounts by assigning part of the fortification to Hadrian and part to Severus—for instance, the earthen mounds to the former and the stone wall to the latter; but a careful study of the existing remains does not favour these theories. It seems better to admit that the writer was careless and forgetful, and that British affairs and the story of the Roman wall were of infinitely less importance to him than they are now to us, dwellers in Britain.
Severus was doomed to discover, like Edward Plantagenet a thousand years later, how deceptive were victories over the Northern mountaineers. Next year (211) the Mæatæ were again up in arms and were joined by the Caledonians. Filled with wrath he ordered his troops again to invade their land, repeating often the lines of Homer:—
Let not one of the race escape the steepness of ruin,
None, your avenging hands, not e’en the babe at the bosom.
He was preparing himself once more to set forth in his litter in the short dark winter days for the northern moorlands, when sickness attacked him, aided, some men thought, by Caracalla and the physicians, and on February 4, 211, the old man died at Eburacum. He had lived sixty-five years and reigned seventeen, and he was the last Roman emperor of whose doings in our land we have any detailed description. Scarcely had Severus died when his sons, renouncing apparently all thoughts of vengeance on the Caledonians, left the wintry north and returned to the delights of Rome. The hardly suppressed enmity of the brothers now broke out into open flame; and after various ineffectual attempts, always foiled by the younger man’s vigilance, Caracalla’s centurions slew Geta in his mother’s arms. Wheresoever the name of his victim occurred on the monuments, it was erased by order of the murderer. This strange manifestation of posthumous vindictiveness has left traces in our own country (for instance on a monument in the abbey-church of Hexham) as well as on the Arch of Severus in Rome, and in an inscription near the Second Cataract of the Nile.
Caracalla himself was assassinated in 217, but emperors of his kindred wore the imperial purple down to the year 235, and thus the dynasty of Severus may be said to have lasted for more than forty years. Both in coins and inscriptions the princes of this house have left an exceptionally full record in the British province. From 235, the date of the murder of Severus Alexander (an excellent young emperor, last of his line), down to 284, a period of almost half a century, the Roman empire was in a state of absolute disintegration. The barbarians were pressing fiercely on its frontiers. This was the era of the first and terrible invasion of the Goths (244–270), an invasion which after awful losses on both sides, and the death of a Roman emperor from the pestilence caused by the war, ended in the abandonment to the barbarians of the great province of Dacia, won for the empire by the victories of Trajan. It was the era, too, of a most humiliating defeat by the Persians, and the conversion of a Roman emperor into a footstool for the Persian king. But more dangerous, if possible, than the external foes of the empire, was its internal disorganisation. In these forty-nine years no fewer than fifteen emperors were recognised at Rome, besides a multitude of obscure competitors (commonly known as the thirty tyrants) in the provinces. It is needless to say that the reigns, which thus lasted on an average little more than three years, were generally terminated by mutiny and murder; needless to dilate on the miserable collapse of law and order which inevitably followed from such continual changes in the depositary of supreme power in the state. Of this dismal period there is, naturally enough, no written record in the annals of Britain. Undoubtedly the wave of Roman influence ebbed; we can hardly be wrong in thinking that now, at any rate, if not before, the country between the two walls was permanently abandoned to the barbarians. The Northumbrian camps were probably also sacked, and we may, if we will, read some pages of that long unwritten chapter in the ruined walls of the camps erected by Hadrian and Severus, in the places where fire has evidently passed upon the corridors of a Roman villa, destroying the elaborate bathing arrangements of tribune or centurion.
For the empire as a whole this interregnum of anarchy came to an end in the year 284 when Diocletian, the second Augustus, ascended the throne. This man, of obscure, even of servile origin, showed statesmanship of a rare order, rescuing the water-logged and all-but foundering vessel of the state from destruction, and steering it into a harbour in which it rode safely for a hundred years. His chief expedient was the division of the imperial power, in recognition of the fact that the vast fabric of the empire could no longer be upheld by a single ruler, and that if the supreme Augustus would not have rivals he must have partners. Dividing the empire into four great sections called prefectures, he chose for himself the prefecture of the East, including Egypt, Syria, Asia Minor and Thrace. His contemporary and colleague, the stout old soldier Maximian, who, like himself, bore the title of Augustus, ruled Italy, southern Germany and the greater part of Roman Africa. After Diocletian had reigned seven years he associated with himself in addition two junior partners, not Augusti but merely Cæsars; Galerius who governed the Illyrian lands, which in the meaning then given to the name stretched from Cape Matapan to the Danube. To the youngest of all, Constantius Chlorus, was assigned the prefecture of the west, stretching from Tangier to Hexham, and including three great “Dioceses” as the divisions intermediate between prefectures and provinces were called: Western Africa and Spain, Gaul and Britain. A noble portion was this, for the junior partner of the imperial firm, and one which might have satisfied the ambition even of a Napoleon. But there was one annoying drawback to the greatness of the western Cæsar. After all the rest of the empire had been restored to tranquillity the island of Britain still remained outside the imperial orbit, and what made this circumstance the more exasperating was the remembrance that it was due to the treachery of an officer chosen by the emperors themselves. Desiring to check the piratical expeditions of the Franks and Saxons who were already beginning to infest both coasts of the British channel, Maximian, who was at that time ruling and warring in Gaul, had entrusted the command of a naval squadron to a certain Carausius, a man of mean extraction, born either in Flanders or Ireland,[17] who had already distinguished himself by his bravery and his skill in naval warfare. From his strong place of arms at Gesoriacum (Boulogne), Carausius soon made his power felt by the barbarians, but before long Maximian had reason to suspect that the officer of the empire was himself in secret league with at least some of the pirates and shared their plunder. He summoned Carausius to appear before him, but that astute personage, suspecting the motive for the summons, hastily quitted Boulogne and sailed for Britain, which in the disorganised condition of Roman affairs he had not much difficulty in making his own.
Having declared himself emperor and having even constrained the two legitimate Augusti to recognise him as a quasi-partner of their dignity, Carausius actually succeeded in maintaining his position for six years (287–293), perhaps the only time in the history of our island when there has been a veritable “Emperor of Britain”. Of the character of his government we have unfortunately no information except some sentences of invective from professional rhetoricians; but at least the numismatist has reason to remember his reign which has supplied our museums with a multitude of coins. In these, while the obverse represents the head of the self-made emperor, a middle-aged common-place man who looks like a self-made manufacturer, the reverse bears sometimes the well-known Roman emblems of the wolf and the twins; or a lion with a thunderbolt in his mouth symbolises the valour of Augustus; or a female milking a cow the fertility of his kingdom; while in some of them the association with Jovius and Herculius (the titles of the two legitimate Augusti) attests his share in the imperial partnership.
Notwithstanding this interchange of compliments it was felt at headquarters that it was time that this separatist empire should come to an end, and it was in fact chiefly to accomplish this that Constantius had been created Cæsar of the west. The history of the campaign has to be gathered with difficulty from the rhetoric of Mamertinus and Eumenius, two professional panegyrists of the conqueror, but we seem to perceive that Carausius or his pirate allies still held the harbour of Boulogne, and that it was necessary to seal up the channel with beams of timber and cargoes of stone to prevent their exit. Stormy weather then delayed for some time the operations of Constantius, and meanwhile Carausius had been assassinated by one of his officers named Allectus, who at once assumed the purple and struck coins describing himself as Pious, Fortunate and August.
For nearly three years Allectus reigned. At last, in 296, Constantius set forth for the overthrow of this new usurper. “Other emperors,” cries his flatterer, “have received the credit of victories won under their auspices though they themselves were tarrying in Rome. You, unconquered Cæsar! put yourself at the head of your troops; you gave the signal to start, when sea and sky were alike turbid, notwithstanding the hesitation of the other leaders. The wind struck obliquely on your sail: you made your vessel tack. All the soldiers, enraptured, cried: ‘Let us follow Cæsar wherever he leads us’. Fortune did indeed favour you. We have heard from the companions of your voyage how the mists hung low over the back of the sea so that the hostile fleet stationed in ambush round the Isle of Wight never saw you pass. As soon as they touched the shore of Britain your unconquered army set fire to all their ships, urged surely, by some warning voice of your divinity, to seek their safety only in fight and victory.” And so, with more of these pompous periods, the orator describes how the usurper Allectus fled as soon as he saw the imperial fleet, and fleeing fell into the hands of the soldiers of Constantius, how half dead with terror he thus hastened to his death, and by his neglect of all military precautions handed over an easy victory to the imperial troops. “Scarcely one Roman was killed while all the hills and plains around were covered with the ugly bodies of the slain. Those dresses worn in barbarian fashion, those locks of bright red hue were now all defiled with dust and gore. That standard bearer of rebellion himself [Allectus], having in the hope of concealment stripped off the purple robe which he had degraded by wearing it, now lay with scarce a rag to cover his nakedness.”[18] The orator then goes on to describe in words of turgid obscurity how some of the soldiers of Constantius, parted from the main body of the fleet in the fog which had baffled the look-out of Allectus, wandered to the “oppidum Londiniense,” and there were fortunate enough to meet and defeat the remains of the “mercenary multitude” of the usurper’s forces which had taken refuge in that town. We thank even the bombastic orator for some slight indication of what was passing in the streets of the little Roman London at the end of the third century.