Another tid bit explanation...
Now, from their conquerors, the Britons learnt many useful arts, to read and to write, to build houses and to make roads; but at the same time, they unlearnt some of their own virtues and, among others, how to think and act for themselves. For the Romans never allowed a Briton any real part in the government of his own country, and if he wished to become a soldier, he was sent away from Britain to serve with a legion stationed in some far-distant part of the empire.
Thus it came about that when, in the fifth century, the Romans withdrew from Britain to defend Rome itself from invading hordes of savages, the unhappy Britons had forgotten how to govern and how to defend themselves, and fell an easy prey to the many enemies waiting to pounce on their defenceless country.
Picts from Scotland invaded the north, and Scots from Ireland plundered the west; worst of all, the heathen Angles and Saxons, pouring across the seas from their homes in the Elbe country, wasted the land with fire and sword. Many of the Britons were slain; those who escaped sought refuge in the mountainous parts of the west from Cornwall to the Firth of Clyde. There, forgetting, to some extent, their quarrels, they took the name of the Cymry, which means the "Brethren," though the English, unable to understand their language, spoke of them contemptuously as the "Welsh," or the "Strangers."
