Duke of Normandy
Duke of Normandy was the title given to the rulers of the Duchy of Normandy in northern France, a fief created in AD 911 by King Charles III "the Simple" of France for Rollo, a Norse nobleman, leader of "Northmen".
In 1066 the reigning duke, William II "the Bastard", conquered Brittany and then England, whereupon he became known as King William I "the Conqueror" of England. From then on, the duke of Normandy and the king of England were usually the same man, until the king of France seized Normandy from King John in 1204. John's son Henry III renounced the ducal claim in the Treaty of Paris (1259). Thereafter, the duchy was given at least four times to members of the French royal family, until the French Revolution and the dissolution of the French monarchy in 1792.
Rollo the Viking 
After participating in many Viking incursions along the Seine, culminating in the siege of Paris in 886, Rollo was finally defeated by King Charles the Simple. With the Treaty of St.-Claire-sur-Epte, Rollo accepted to become a vassal to Charles III of France, converted to Christianity and was baptized with the name Robert. Charles then granted Rollo territories around Rouen, which came to be called Normandy after the Northmen (Latinised Normanni).
Rollo and his immediate successors were styled as "counts" of Normandy. Some later medieval sources refer to them by the title dux, the Latin word from which the English word "duke" is derived; however, Rollo's great-grandson Richard II was the first to assuredly be styled "Duke of Normandy".
Although certain titles were used interchangeably during this period, the title of "duke" was typically reserved for the highest rank of feudal nobility — either those who owed homage and fealty directly to kings, or who were independent sovereigns (primarily distinguished from kings by not having dukes as vassals).
William the Conqueror 
William the Conqueror added the Kingdom of England to his realm after the Norman Conquest of 1066. This created a problematic situation wherein William and his descendants were king in England but a vassal to the king in France. Much of the contention which later arose around the title Duke of Normandy (as well as other French ducal titles during the Angevin period) stemmed from this fundamentally irreconcilable situation.
After the death of William the Conqueror, his eldest son, Robert Curthose, became Duke of Normandy while a younger son, William Rufus, became King of England. William II was succeeded in 1100 as King of England by another brother, William the Conqueror's youngest son, Henry I. When Henry deposed Robert in 1106 he claimed both titles, Duke of Normandy and King of England, uniting them once again.
International contention 
In 1204, King Philip II of France confiscated the Duchy of Normandy, held at that time by King John of England, and subsumed it into the crown lands. Only the Channel Islands [a] and Calais remained under John's control. In 1259, Henry III of England recognised the legality of French possession of mainland Normandy under the Treaty of Paris.
With the Treaty of Troyes in 1420, Henry V of England temporarily regained all territories formerly held by the Plantagenets, including Normandy, and was made regent and heir of France. His son, Henry VI inherited both kingdoms in 1422 and afterwards English monarchs included King of France among their list of titles. They also included the Royal Arms of France in their own armorial achievements, even after they had lost their French possessions (with the exception of Calais) after 1450.
British claims to the throne of France and other French claims were not formally abandoned until 1801, when George III and Parliament, in the Act of Union, joined the Kingdom of Great Britain with the Kingdom of Ireland and used the opportunity to drop the obsolete claim on France. By that time, the French monarchy itself had been overthrown in 1792 with the establishment of the French Republic. The French revolution also brought an end to the Duchy of Normandy as a political entity, as it was replaced by several départements.
Channel Islands 
Although the British monarchy relinquished claims to continental Normandy and other French claims in 1801, the Channel Islands (except for Chausey under French sovereignty) remain Crown dependencies of the British Crown to this day. Unlike the Isle of Man, these islands have no specific title pertaining to them (that is: the British monarch is not styled Duke or Duchess of Normandy in relation to the Islands). The Loyal Toast in the Channel Islands is La Reine, notre Duc or The Queen, our Duke (or when the monarch is male, The King, our Duke), as the islands were formerly part of the Duchy of Normandy, the rest of which had been renounced in 1259 under the Treaty of Paris.
List of Dukes of Normandy 
- Kings of England indicated by an asterisk (*)
Early Dukes of Normandy (911-1204) 
- Rollo 911-927
- William I Longsword 927-942
- Richard I 942-997
- Richard II the Good 996-1027
- Richard III 1027
- Robert I The Magnificent 1027-1035
- William II the Conqueror* 1035-1087
- Robert II Curthose 1087-1106
- Henry I Beauclerk* 1106-1135
- William III Atheling (Under his father, Henry I)
- Stephen of Blois* 1135-1144 (usurped from Matilda)
- House of Plantagenet
- Geoffrey Plantagenet 1144-1150 (jure uxoris)_
- Henry II* 1150-1189
- Richard IV Lionheart* 1189-1199
- John I Lackland* 1199-1216, lost mainland Normandy in 1204.
- Henry III* 1216–1259, renounced mainland Normandy and the ducal title by Treaty of Paris (1259).
Later Dukes of Normandy (1204-1792) 
In 1204, the King of France confiscated the Duchy of Normandy (with only the Channel Islands remaining under English control) and subsumed it into the crown lands of France. Thereafter, the ducal title was held by several French princes.
In 1332, King Philip VI gave the Duchy in appanage to his son John, who became king as John II in 1350. He in turn gave the Duchy in appanage to his son Charles, who became king as Charles V in 1364. In 1465, Louis XI, under constraint, gave the Duchy to his brother Charles de Valois, Duke of Berry. Charles was unable to hold the Duchy and in 1466 it was again subsumed into the crown lands and remained a permanent part of them. The title was conferred on a few junior members of the French Royal Family before the abolition of the French Monarchy in 1792.
- John (son of King Philip VI, later King John II of France) 1332-1350.
- Charles (son of John II of France, later King Charles V of France) 1350-1364
- Charles (brother of Louis XI of France. Also Duke of Berry.) 1465-1466
- Louis-Charles (son of Louis XVI, later Dauphin 1789-1791 and titular King Louis XVII, 1792-1795.) 1785-1789.
On 31 December 1660, a few months after the restoration of Charles II to the thrones of England and Scotland, King Louis XIV proclaimed Charles' younger brother James, Duke of York, "Duke of Normandy". This was probably done as a political gesture of support for James. 
- When the Contentin Peninsula was lost to Normandy by Brittany, this newly gained territory included these Channel Islands.
- I. J. Sanders (January 1951). "The Texts of the Peace of Paris, 1259". The English Historical Review (Oxford University Press) 66 (258): 81–97. From JSTOR, courtesy of The Wikipedia Library; subscription required.
- Cawley, Charles (2008-10-28), England Kings: Henry King died 1183, Foundation for Medieval Genealogy, retrieved August 2012,[better source needed]
- Weir, Alison (1996). 258. Britain's Royal Families: The Complete Genealogy. Revised Edition. Random House, London. ISBN 0-7126-7448-9.
- Onslow, Richard (Earl of Onslow). The Dukes of Normandy and Their Origin. London: Hutchinson & Co., 1945.
- The Dukes of Normandy: From Rollo to William of Normandy
- British Monarchy web page about the Channel Islands