The surrender of the whole of present-day Normandy by the Frankish kings to the Norwegian Rollon (the future Robert I) and his descendants was made in three steps : the area of  today’s Upper Normandy in 911, the Hiemois (Falaise region) and the Bessin in 924, and the Cotentin and the Avranchin in 933.

> The Scandinavian colonization : took place especially during the first half of the tenth century. Although few in numbers, the invaders were exclusively masculine. In some restricted areas, the colonization was more thorough, notably in Hague and in the Saire Valley coastal region. Land was divided among the soldiers whom the new masters wished to reward. In this way, Henne, Skelder, Otti and Torlach received lands which became Hainneville, Equeurdreville, Octeville and Tourlaville.

The change of sovereignty was rapid in the political sense but made slow progress as far as territorial, religious and administrative organization was concerned. This was put into place by the first Dukes; Guillaume-Longue-Epée, Richard II, Richard III and Robert I. The latter recognized his illegitimate son, William, born in 1027, as heir to the Ducal crown.

> The Norman Conquest : In 1065, Edward III of England, designated Duke William, his distant relative as his successor, with the approval of the Lords of the kingdom including his brother-in-law Harold. However, when Edward died, Harold proclaimed himself King.

> 1066 : After the Battle of Hastings, the Duke of Normandy took possession of England.

> The Plantagenet state : In 1120, the sons of Henri Beauclerc died during the shipwreck of  the "Blanche Nef"  near present-day Gatteville Lighthouse on North East of the Cotentin. Henri demanded his vassals to swear allegiance to his daughter Mathilda, who married Geoffroy Plantagenet, Count of Anjou, Maine and Touraine.

> December 1135 : Upon the death of Henri Beauclerc, his nephew, Etienne de Blois, went to England and proclaimed himself King. Thus began the war between Etienne and Geoffroy, Duke of  Normandy. The conflict did not end until 1154 with the death of  Etienne de Blois who had designated Henry II as his successor.

> 1152 : The King of France, Louis VII committed the grave political error of repudiating his wife Eleanor of Aquitaine who then married Henri Plantagenet. Henri, being at the same time Duke of Normandy and King of England, added Aquitaine, Poitou, Auvergne  and Perigord to his domains by this marriage. Because of structures instituted by the first Dukes, he was able to create, from legislative, economic and political points of view, the most remarkably organized state in the Western world.