After the death of Severus, a long period elapsed, in which the Roman historians observe a profound silence respecting the affairs of Britain. Local records and native historians supply but feebly the deficiency. During the reign of Gallienus, which extended from A.D. 260 to 268, a large number of usurpers arose, who are commonly denominated the Thirty Tyrants. Of these Lollianus, Victorianus, Postumus, the two Tetrici, and Marius, are supposed to have assumed the sovereignty in this island; for their coins have been dug up more abundantly here than elsewhere.
BRITAIN REVOLTS.
Diocletian commenced his reign in the year 284. Though he was a man of energy and ability, the care of a crumbling empire was too much for him, and he divided his honours and anxieties with Maximian. Increasing perplexities a few years afterwards induced the emperors to appoint two Cæsars. Diocletian chose Galerius Maximianus, and Maximian nominated Constantius Chlorus. To Constantius was assigned the charge of Britain, where he eventually found a grave. He was the father of Constantine the Great.
CARAUSIUS ATTAINS THE SOVEREIGNTY.
During a portion of the united reign of Diocletian and Maximian, Britain assumed an independent position. In order to repress, in the northern seas, the ravages of the Franks and Saxons, who about this period began to demand a place in the world’s history, Carausius was appointed to the command of ‘the channel fleet.’ Gesoriacum, the modern Boulogne, was his place of rendezvous. Carausius, who was an expert seaman, exerted himself, at first, with extraordinary success, against the pirates. Afterwards, it was observed that he consulted his own interest, rather than the public service. The emperors resolved upon his destruction. Carausius, stimulated by self-preservation, as well as ambition, entered into an alliance with his former foes, the Franks and Saxons, and declared himself emperor of Britain. He was favourably received by the natives of the island, and for seven years wielded the sovereignty of his empire with vigour and ability. He repelled the Mæatæ and the Caledonians, and having subdued these tribes, attached them to his interest. Nothing, observes Mr. Thackeray, can more fully prove the maritime strength and resources of Great Britain, under an able ruler, than the fact, that Carausius for seven years bade defiance to the Roman power; and at the end of that time fell, not overcome by the imperial forces, but by private treachery. Never before, nor until several hundred years after this period, was the country firmly united under the government of one sovereign.
Constantius was preparing to invade Britain with a fleet of a thousand ships, when Carausius was murdered by Allectus, whom he had trusted as his dearest friend. For about three years the assassin held, though with a less firm grasp, the power formerly possessed by his victim.
THE SUCCESSES OF CARAUSIUS.
A very numerous suite of coins commemorates the successes of Carausius, and vindicates his claim to a share in the empire of the world. Two coins are represented here. On the reverse of one is a galley, which indicates the chief source of his strength, and on the reverse of the other is a lion with a thunderbolt in its mouth, significative, not only of the bold bearing which the ancient sea-king assumed, but of that which his successors in modern times have maintained.
Carausius, according to Macpherson, is the Caros of Ossian. The following extract, upon this supposition, contains a remarkable allusion to the Wall.