Duke of Normandy

In the Middle Ages, the Duke of Normandy was the ruler of the Duchy of Normandy in northwestern France. The duchy arose out of a grant of land to the Viking leader Rollo by the French king Charles III in 911. In 924 and again in 933, Normandy was expanded by royal grant. Rollo's male-line descendants continued to rule it down to 1135. In 1202 the French king Philip II declared Normandy forfeit and by 1204 his army had conquered it. It remained a French royal province thereafter, still called the Duchy of Normandy, but only occasionally granted to a duke of the royal house as a apanage.

There is no record of Rollo holding or using any title. His son and grandson, William I and Richard I, used the titles "count" (Latin comes or consul) and "prince" (princeps). Prior to 1066, the most common title of the ruler of Normandy was "Count of Normandy" (comes Normanniae) or "Count of the Normands" (comes Normannorum). The title Count of Rouen (comes Rotomagensis) was never used in any official document, but it was used of William I and his son by the anonymous author of a lament (planctus) on his death. Defying Norman pretensions to the ducal title, Adhemar of Chabannes was still referring to the Norman ruler as "Count of Rouen" as late as the 1020s. The late 11th-century Norman historian William of Poitiers used the title "Count of Rouen" for the Norman rulers down to Richard II. Although references to the Norman rulers as counts of Rouen are relatively sparse and confined to narrative sources, there is a lack of documentary evidence about Norman titles before the late 10th century.

The first recorded use of the title duke (dux) is in a act in favour of the Abbey of Fécamp in 1006 by Richard II. Earlier, the writer Richer of Reims had called Richared I a dux pyratorum, but which only means "leader of pirates" and was not a title. During the reign of Richard II, the French king's chancery began also called the Norman ruler "Duke of the Normans" (dux Normannorum) for the first time. As late as the reign of William II (1035–87), the ruler of Normandy could style himself "prince and duke, count of Normandy" as if unsure what his title should be.

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