A falling empire
Among the reasons for the Empire's failure was the leadership at the very top. From around 200-400 AD, the later Emperors frequently rose to and fell from office, with struggles for power becoming commonplace.
By the end of the third century the Roman Empire was split in two. In 293 the Emperor Diocletian established an autocratic government and created the Tetrarchy, dividing the Empire into Western and Eastern portions to ensure its survival.
Each was to be ruled by an Augustus, and supported by a Caesar, to ensure a smooth succession of power. Diocletian became Augustus of the Eastern Empire, with Galerius as his Caesar. Constantius Chlorus (the Pale) was appointed Caesar to the Western Augustus, Maximian.
Brittania for a time had its own Emperors. In late 286 or early 287 a usurper, Carausius, declared himself Emperor of Britain and northern Gaul, although it was short lived. He was assassinated in 293 by his treasurer, Allectus, acting on the orders of Constantius.
Allectus took command of Britain until 296, but he in turn was defeated when Constantius sent Asclepiodotus, a prefect of the Praetorian Guard, to invade. The assassination restored Roman rule in Britain once again.
By 312 the governance of Brittania was divided into four, as part of administrative reforms under the aegis of Diocletian. One of the new provinces was Britannia Prima, which encompassed Wales and much of what is now south western England. Its capital was in Cirencester.
However, the stability of power wasn't to last, and by the latter half of the fourth century barbarian uprisings on the borders were commonplace.
There were also ambitious army leaders who sought to usurp the Emperor. In 383, Magnus Maximus denuded Britain of its garrison in his campaign to win the title.
Equally significant is the challenge represented by peoples living beyond the imperial frontier. In 410, Rome itself was occupied by the Gothic forces of Alaric and the Emperor had no alternative but to urge the men of Britain to organise their own defence.
They were hard pressed, for they faced the attacks of the Picts from the north, the Irish from the west and the Saxons from the east.
Their efforts to maintain a self-governing Britannia were not without their successes, which included the almost mythical campaigns of King Arthur. But eventually the tide turned and the nations of the Welsh, the English and the Scots were born.
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