Duke of Normandy
The title Duke of Normandy was held by the rulers of Normandy from Rollo in 911.
In 1066 Duke William II became King William I of England, and was held by the Kings of England until Henry III renounced (gave up) the title by treaty in 1259. King John had lost mainland Normandy in 1204, and kept only the Channel Islands. Today the Channel Islands still owe allegiance to the King or Queen of Britain.
In 1660 when King Charles II was restored to the throne, the King of France, Louis XIV, created Charles brother James Duke of Normandy, probably as a show of support for monarchy and to stop Charles claiming the title himself.