East Anglia was a long-lived Anglo-Saxon kingdom in which a duality of a northern and a southern part existed, corresponding with the modern English counties of Norfolk and Suffolk. It was formed during the 5th century, following the ending of Roman power in Britain in 410. The east of Britain became settled at an early date by Saxons and Angles from the continent. During the 5th century, groups of settlers of mixed stock migrated into the Fens and up the major rivers inland. From Bede it is known that the people who settled in what became East Anglia were Angles, originally from what is now part of Denmark. By the 6th century, new settlements had also appeared along the river systems of the east coast of East Anglia, including the Deben, the Alde and the Orwell. The settlers were unaffected by Roman urban civilisation and had their own religion and language. As more of the region fell under their control, new kingdoms were formed, replacing the function of the Roman "territoria". Surrounded by sea, fenland, large defensive earthworks such as the Devil's Dyke and wide rivers, all of which acted to disconnect it from the rest of Britain, the land of the East Angles eventually became united by a single ruling dynasty, the Wuffingas.