The fifth century represents a period of enormous upheaval and transition for Britain. Dramatic shifts in political structure; invasions and migrations that thrust new and conflicting cultures onto the natives; and the introduction of Christianity, a culture in itself, forced the Britons to face challenges they had not seen since the Roman conquest four hundred years earlier. This lesson details these wrenching changes.
It appeared that Roman military might would eventually overtake all of Britain and perhaps Ireland as well. But problems on the continent that foreshadowed the future destabilization of the empire prompted troops to be pulled out of Britain. No longer having enough strength to hold the northern frontiers, the occupiers retreated below Hadrian’s Wall. They were never able to advance the frontier northward again.
Late in the third century, ten Roman forts along the southeastern coastline, called the Saxon Shore, were refortified, probably to assist in repelling Frankish and Saxon pirates. By the middle of the fourth century, Picts from the north, Scots from Ireland and Saxons from the continent began fierce attacks against the Britons. The invaders were put down but not contained for long. Meanwhile on the continent, the empire began to falter and was officially divided between east and west in 395. The empire of the east deflected barbarian invasions from Asia into the western empire. The west, depleted of troops to fight them, began to crumble under the weight of so many invaders.
Dismayed with Roman leadership, the armies in Britain began to elect their own emperors from their leaders. A Hispanic-born soldier, Magnus Maximus, was credited with defeating the Picts and Scots in 382. The next year, his followers declared him emperor of the west. Carried along with the usurpation, he took his army to the continent and defeated the real emperor Gratian. Maximus was lauded in early Welsh poetry as Macsen Wledig and was considered Welsh royalty. Theodosius, emperor of the eastern empire, defeated and executed Maximus in 388.
Other military emperors were subsequently declared. They continued to drain the legions from Britain, evacuating them for use on the continent. The last of the legions were pulled out around AD 408-410, essentially severing Britain from the empire. Britain was left to rule herself and defend her shores against invaders. Several appeals for help followed, most notably to Aetius in 446. The appeals went unanswered. The western empire fell apart, officially ending in 476.