Peter Ackroyd > Anglo-Saxon civilization was created by a pandemic.
He's referring to the largely un-sung plague of the 540s, probably bubonic or pneumonic, which emerged out of Egypt and devastated the late (or sub) Roman world.
It seems that for some reason the 'native' inhabitants of Britain, my own paternal ancestors, were more adversely affected by this pestilence than the Anglo-Saxons, at that time established mainly along the eastern side of the island.
The population catastrophe amongst the Britons of the west permitted Saxon leaders like Ceawlin to penetrate the wealthy agricultural heartlands of Salisbury Plain towards the end of the sixth century.
The western saxons established their own kingdom of Wessex, which would ultimately evolve into the kingdom of England.
Meanwhile many Britons shifted across the water having concluded that life is all right in Armorica, thus founding the semi-independent cultural enclave that came to be known as Britanny.
Some of these Bretons would be back several centuries later on as a key part of the Duke of Normandy's invading army in 1066.
My next door neighbour during my fresher year at Girton was one Gus Le Breton.