I was just wondering if people generally felt if the success of the Great Heathen Army was more down to luck or skill of the Viking warriors. For example, the fact they only gained a foothold because of in-fighting between the Deirans and Bernicans. Also the magnitude of the impact of the Norse on Brythonic, Gaelic and Brythonic culture? I personally find it that the Anglo-Saxon invasion didn't introduce many new Germanic genes and therefore most Anglo Saxons were genetically British whereas the Viking conquests resulted in migrations of Scandinavians, changing the ethnicity of the natives considerably.