The sack of Lindisferne

 Anno 793 the great house of religion at Lindisferne was sacked by the Vikings, giving start to the Danish invasions of Great Britain. But the catastrophe only fired up English religious fervor. King Burgred of Mercia retired to a monastery when the Danes conquered his kingdom, and many royal princesses entered nunneries in their widowhood. The pilgrimage to Rome was very popular, although disastrous for females, as Cuthbert wrote "There are indeed few cities in Lombardy, or in France, or in Gaul, in which there is not an adulteress or harlot of the English race". Leofgifu, a London woman, died on the road to Jerusalem in about 1060. A Lincolnshire thane called Ulf set out for Jerusalem just before the Norman conquest and was never heard about again. West Saxon Wynfrith who took the name of Boniface became the archbishop of the Germans and it may be said that Western Europe was converted by English missionaries. 

All that from a book by D. Whitelock.

Then, in 1066 the Normans crossed the Channel, and divided the country among 180 Norman tenants-in-chief and innumerable mesne (intermediate) tenants, all holding their fiefs by knight service. The replacement of the English aristocracy with a Norman one was paralleled by similar changes of personnel among the clergy. The Saxons became the lower class and even today, a thousand years later, old French family names are frequent in England's aristocracy.