During the third century the empire was agitated by numerous competitions for the purple, but it was somewhat appeased on the accession of Diocletian. The legions in Britain now adopted the practice of setting up emperors of their own. One of them, Carausius, reigned from 287 to 294, and was only got rid of by assassination. The murderer, Allectus, attempted to succeed him, and maintained himself in the island till defeated by Constantius, who was created a sub-emperor, with the title of Cæsar; thus Britain was once more united to the empire. The victor made himself loved by the Britons, by his equitable and wise administration, and continued to reside amongst them till the abdication of Diocletian. At his death, which occurred in York in 306, he recommended to the army, who were devoted to him, his son, the celebrated Constantine, who was immediately saluted emperor and Augustus. He was beloved by the Britons, being the son of a British mother, the "fair Helena of York."
Constantine was a Christian, but, before his accession, had been compelled to execute the imperial commands against the followers of that faith. Many of the Romans, who had received the new religion, and fled from the persecutions of Claudius and Nero, found refuge in Britain, where the imperial edicts were less rigorously obeyed, till the persecution of Diocletian, when the churches throughout the empire were ordered to be closed, and the refusal of the new sect to offer sacrifice to the gods of Rome was punished with death. Much as Constantine condemned, he dared not annul the impious mandate he had received. Ascending his tribunal, before which the principal officers of his army and household had been summoned, he read aloud the edict, and added that those who professed the new faith must decide on abandoning either their faith or their employments. Many, doubtless, chose the former alternative; since we are told that the prince, in great indignation, dismissed the apostates from his service, observing that it was impossible for him to trust those who had denied their convictions. His lieutenants, however, were less scrupulous, and Christian blood was shed to maintain the State religion of the empire. Alban, the protomartyr, as the latter designation implies, was the first who suffered; and the names of Julius and Aaron, citizens of Caerleon, upon the Usk, have also been handed down to posterity as two of the earliest victims. But on the accession of Constantine to the throne, religious toleration was restored throughout the empire. Christianity now made rapid progress in the island. A hierarchy became established, and at the Council of Arles, in 314, three English bishops assisted—those of York, London, and Camulodunum.
After the death of Constantine the Caledonians disappear and are replaced by the Picts. There is every reason to believe, however, that these are only two names for the same race, the Picts (picti) being the "painted" or "tattooed" men. The Scots, another race of northern invaders, were of different origin: they originally came over from Ireland, where they inhabited the eastern coasts, settled in the neighbourhood of Loch Lomond, and made an alliance with the nearest tribes, for the purpose of ravaging the possessions of the Britons. Both these peoples were of Celtic origin, and the Scots, or Milesians (from Lat. miles, a soldier), were the dominant race in Ireland. Other plunderers also attacked the weakened empire, of whom the most important were the Saxons, of whom we shall read more later on.
They were severely chastised by Theodosius, who visited Britain in 343. He succeeded in expelling them from the Roman provinces and driving them back to their wild retreats.
Maximus, who afterwards assumed the title of Augustus, while in Britain, carried on the war against the Picts and Scots with unrelenting severity; his ambition, however, led him to attempt the conquest of the whole western empire, in which he failed, and was beheaded at Aquileia. His army, comprising a large majority of Britons, never returned to their native country, which consequently was left in a great measure defenceless. So favourable an opportunity did not escape the vigilance of the Picts and Scots, who made successive inroads in the island, and returned to their mountain fastnesses laden with plunder.
The power of Rome was now shaken by the irruption of barbarians of various denominations, who, issuing from the east and north, depopulated her fairest provinces. Assailed at so many points at once, it seemed as if the nations of the earth had been let loose to uproot her supremacy, and break the shackles which for so many ages had fettered the greater part of the world. The Goths, led by Alaric, crossing the Julian Alps, swept like a torrent over the fertile plains of Italy. Other German tribes devastated Gaul, and the Roman legions in Britain, deprived of all communication with the Emperor Honorius, fell back upon their custom of electing an emperor for themselves.
The first whom they selected for the purple was Marcus, whom his soldiers, very soon after elevating him to the imperial dignity, put to death; after him came an adventurer named Constantine, who paid for his short-lived dignity with his life. A third usurper arose in Gerontius.
ROMAN SOLDIERS LEAVING BRITAIN. (See p. [18.])