The Duke of Normandy is a title held (or claimed) by various Norman, English, French and British rulers from the 10th century. The Duchy of Normandy was created in 911 for the Viking leader Rollo.
As his predecessors were styled jarl of the Northmen (Normans), Richard II was the first to be formally styled duke of Normandy.
In 1066, William the Bastard added the kingdom of England through the Norman Conquest.
In 1204, the continental lands of the Duchy were taken over by the French King Philip Augustus but the English kings continued to claim the title of Duke until the Treaty of Paris of 1259, when they gave up their claims to it. English monarchs made subsequent attempts to reclaim their former continental possessions, particularly during the Hundred Years' War.
However English monarchs have continued to rule the Channel Islands, a part of the Duchy since 933, being known traditionally in the Islands as Duke of Normandy.
On several occasions, the Duchy was given out as an appanage for a member of the French royal family, most notably by Philip VI for his eldest son, the future King John II; by John II for his son, the future Charles V, who was, however, usually known as the Dauphin; and by Louis XI for his brother Charles, usually known by his other title of Duc de Berri.
The future Louis XVII was also known as Duke of Normandy before his elder brother's death in 1789.
Succession of the Dukes of Normandy