The Normans were descendants of Vikings settled from 911. They adopted French language and Christianity and built a powerful duchy facing the Capetians.
Duchy of Normandy
From Rollo to the 11th century the duchy became one of the best-organised principalities in the West.
1066 and after
William’s conquest of England made the Norman dukes kings overseas—a dual role that shaped Capetian policy and later the Hundred Years’ War.