I learned yesterday that if you want to thank, or blame, anyone for the "1066 and all that", perhaps it should be a nine-year-old girl called Cecilia.
She was the daughter of William the (to be) Conqueror and his queen Matilda, and she was given to a monastery in France before the invasion set out to help to ensure God's blessing on the expedition. She became a great abbess at Caen. There's a geneological summary here.
This was at a Historical Association talk at the Swedenborgh Society in Bloomsbury; a lovely hall very evocative of 19th-century "self-improvement".
The Historical Association local branch programme can be found here.