One most important fact must be kept steadily in mind: the Army of Britain, though it contained some foreign corps and a large number of soldiers of foreign extraction, was in the main British in composition and feeling. For centuries the troops of each Roman province had been very largely recruited locally, either by conscripts or the children of the soldiers themselves, often trained to camp-life and war from their youth up. A so-called Moorish cohort would perhaps not contain a single Moor, and so on throughout the army. A regiment stationed in Britain kept its name, but was made up with British recruits.
In 402 King Alaric and the Visigoths set out to invade Italy, and Stilicho was forced to weaken the Army of Britain for the defence of Ravenna and Rome. Among the troops withdrawn was the VIth Legion—its long residence at York at last at an end—and none of them ever came back; for though Stilicho hurled invasion after invasion out of Italy, on January 1, 406, a horde of Teutons poured over the frozen Rhine and began to waste Gaul. Like an army whose line has been pierced, the provinces found the Germans interposed between them, and Britain was cut off from Italy.
Thereupon the Army of Britain appears to have decided that Honorius and Stilicho were useless as defenders of the Empire, and resolved to save it themselves—by mutinying! They selected a certain Marcus as emperor, and almost immediately murdered him. A second, named Gratianus, had the same fate; but the third, Constantine, was made of sterner stuff, and wore the purple for over three years—perhaps because he was wise enough to leave Britain. He decided to imitate the example of ‘Maxim Gwledig,’ and crossed to Gaul in 407. This is the event so often, and wrongly, called the ‘departure of the legions.’
Constantine had been chosen Emperor in order to carry out the task with which Stilicho had failed to successfully grapple. Is it to be supposed that he would have dared to leave Britain defenceless, even had he so desired? The idea is absurd. He no doubt took to Gaul a considerable force, which must have been mainly British, and his chief general, Gerontius (Geraint), was a Briton. But to suppose that, as Gildas wails, the province was left defenceless, and that the inhabitants were so effeminate and cowardly as to be incapable of bearing arms, cannot be allowed. It is certain that the Britons were among the best fighting peoples of the Empire, and when Constantine crossed to Gaul in 407 he undoubtedly left his base properly garrisoned. It is not even certain that the IInd Legion left Britain.
Constantine laid hands on a great part of Gaul and Spain—so far as they were not held by barbarians—and marched down to the Rhone to oust Honorius, who had just murdered his guardian and principal stay, the great Stilicho. Gerontius, however, revolted from him, and in 411 he was besieged in Arelate (Arles), captured, and executed. Meanwhile, what of Britain? In 409 came the first mutterings of the coming storm. The Saxons and their allies made raids both on Britain and Gaul. Thereupon the provincials disowned Constantine, who was clearly no more of a success than Stilicho, expelled his officials, elected others of their own choosing, raised new levies of troops, and repulsed the raiders. This is vouched for by the chronicler Zosimus. The ministers of Honorius, beset by many troubles, had already sent word to the British communities that they must defend themselves, and the provincials probably regarded their action as one of adherence to the legitimate Emperor as against usurpers of the type of Constantine. Certainly there was no conscious withdrawal from the Empire.
The course of events can only be dimly conjectured. In the east the Romanized cities probably took the lead. In the west and north matters went differently. These regions were less civilized, and the political unit was the tribe and not the city. In North Wales Cunedda was practically king, and small monarchial states soon sprang up elsewhere. In the north, about 450, St. Patrick tells us of a military state (Strathclyde), ruled by a chief whom he calls Coroticus, who possessed both a paid army and a fleet, and had not only beaten off the Scots, but had made retaliating raids on Ireland. Both Cunedda and Coroticus are called Gwledig (overlord) in the Welsh genealogies, and Cunedda at least appears to have held the post of Dux Britanniarum (General of the Northern Frontier). Apparently after his death a new state named Reged arose on the Wall; it was founded by Coel—the ‘Old King Cole’ of an irreverent nursery rhyme. Speaking roughly, we may say that in South Wales and Damnonia tribal kingdoms, in North Wales and the north-west military states, were the rule; while the cities apparently kept up Roman traditions, and by means of their walls maintained independence.
It will be seen that in many ways the outlook was bad for Britain. The interests of the military chiefs of the tribal dynasts and of the Romanized cities were certain to diverge, and hostilities between them were almost inevitable. Probably even the cities did not always find co-operation easy. It is possible that there were already numbers of Teutons in the country; there may have been Teutonic settlements on the coast of Lothian as early as 400. The fleet of the Saxon Shore had apparently disappeared, presumably during the troubled period 407-411. Finally, the country lacked the unifying bond of a common religion. It is practically certain that though the Christian Church in Britain was a vigorous organization, its adherents were in a minority. The church at Calleva is so small as to make it certain that the Christian population was only some hundreds in number, the total of inhabitants being, perhaps, 5,000. The fragments of a local god were found by the explorers around its pedestal—i.e., the statue was standing there when disaster overtook the place. When St. Germanus visited Britain in 429 he baptized thousands of converts. Probably in Britain, as elsewhere in the failing Empire, the adhesion of the upper classes to Christianity was nominal or non-existent, as it was to be for some generations; and the majority among the masses was frankly pagan.
Thus divided, distracted, with a defensive system disorganized by repeated withdrawals or shifting of troops, and with little prospect of co-operation between its cities and tribal cantons, Britain had to face attacks from three sides. On the north were the restless Picts, on the west the Scots, on the east the Teutons.
To construct anything like a connected narrative out of the few authorities who shed light on this period is almost, if not quite, impossible. The whole epoch has been called the ‘lost period,’ but it would not be by any means unfair to describe it as neglected. The authorities are scanty, obscure, and hopelessly confused; but it is possible, by careful study, to construct a not improbable skeleton of facts.
From 409 to 429 we have no clear indication of the course of events in Britain. It seems, however, to have been somewhat as follows: