The House of Normandy is the usual name for the family that were the Dukes of Normandy and Kings of England. they were in power from shortly after the Norman conquest of England and lasted until the House of Plantagenet came to power in 1154. It began with Rollo and his descendants, and from William the Conqueror and his heirs down through 1135. Two of William's grandchildren, Matilda and Stephen of the House of Blois argued over the throne ending the dynasty.