[1] https://en.wikipedia.org/wiki/Gytha_Thorkelsd%C3%B3ttir
Edit: Worth listening to are these BBC 4 In Our Time Podcasts.
The Battle of Stamford Bridge: http://www.bbc.co.uk/programmes/b011jvlt
The Domesday Book: http://www.bbc.co.uk/programmes/b040llvb
https://en.wikipedia.org/wiki/Varangian_Guard
"Composed primarily of Scandinavians for the first 100 years, the guard began to see increasing numbers of Anglo-Saxons after the successful invasion of England by the Normans.
[..]
the Guard was commonly called the Englinbarrangoi (Anglo-Varangians) [after a point]"
(That is all I really read about that subject.)
Edit: But please expand on the subject, as if I had meant that. It would be interesting. :-)
Christianity wasn't that nice either. Exterminating all competing religions (Asatru, Catharism, South American religions etc) and probably even worse pogroms than the Muslim world, etc.