The effects of the Norman Conquest on Anglo-Saxon Aristocracy (pdf): https://scholarship.richmond.edu/cgi/viewcontent.cgi?article=1698&context=honors-theses
"Following the conquest, many Anglo-Saxons, including groups of nobles, fled the country for Scotland, Ireland, or Scandinavia. Members of King Harold Godwinson's family sought refuge in Ireland and used their bases in that country for unsuccessful invasions of England. The largest single exodus occurred in the 1070s, when a group of Anglo-Saxons in a fleet of 235 ships sailed for the Byzantine Empire] The empire became a popular destination for many English nobles and soldiers, as the Byzantines were in need of mercenaries. The English became the predominant element in the elite Varangian Guard, until then a largely Scandinavian unit, from which the emperor's bodyguard was drawn. Some of the English migrants were settled in Byzantine frontier regions on the Black Sea coast, and established towns with names such as New London and New York." ... "A direct consequence of the invasion was the almost total elimination of the old English aristocracy and the loss of English control over the Catholic Church in England. William systematically dispossessed English landowners and conferred their property on his continental followers. The Domesday Book meticulously documents the impact of this colossal programme of expropriation, revealing that by 1086 only about 5 percent of land in England south of the Tees was left in English hands. Even this tiny residue was further diminished in the decades that followed, the elimination of native landholding being most complete in southern parts of the country": https://en.wikipedia.org/wiki/Norman_conquest_of_England
Doomsday book, Nobles and Knights: http://www.nationalarchives.gov.uk/domesday/world-of-domesday/nobles.htm
"By William’s death, the Anglo-Saxon aristocracy was all but replaced. In the Domesday book of 1086, there are only four large English landowners".: https://www.thoughtco.com/consequences-of-the-norman-conquest-1221077
etc etc etc