Fernand Braudel: "England acted as a province (or a group of provinces) within the Anglo-French unit "that was "both battlefield and prize" (Braudel 1984 p. 353).
The Kingdom of England was ruled by a Norman-French descendant and Norman-French-speaking aristocracy when this title was first adopted in 1340 by King Edward III, who claimed the throne of France after the death of his uncle Charles IV of France, thereby precipitating the Hundred Years' War. At the time of Charles IV's death in 1328, Edward was his nearest male relative. They were related, however, through Edward's mother Isabella of France. Since the election of Hugh Capet in 987, the French crown had always passed based on male-line relations (usually father to son or brother to brother). There was no precedent for someone succeeding to the French throne based on his maternal ancestry, nor had there needed to be. There had been no shortage of sons and brothers for more than three centuries from the inception of the House of Capet until the early 14th century, when new precedents concerning female inheritance finally had to be introduced. On the death of Charles IV's brother Louis X in 1316, immediately followed by that of his posthumous son John I, it had to be decided whether his young daughter, Joan or his brother Philip would succeed to the throne. The 5th century Salic law was interpreted to mean that no woman could inherit the throne of France, and the throne went to Philip, and after his death, to his younger brother Charles.
At the time of Charles's death in 1328, there was once again a dispute over the succession. Although it had come to be accepted that a woman could not possess the French throne in her own right, Edward III, the nephew of the deceased king, based his claim on the untested theory that a woman could transmit a right of inheritance to her son. This claim was rejected, however, and the throne was given to the male line heir, Philip, Count of Valois, a first cousin to the deceased king. At the time, Edward accepted this result, and did homage to Philip VI for his Duchy of Guyenne. However, disputes over the next 12 years over the precise nature of Edward III's feudal obligations to Philip in Guyenne led to open war in 1337, and to the revival of Edward's claims to the French throne in 1340, when he claimed the title of King of France. By this time, it should be noted, Edward was no longer the closest male heir to Charles IV, as Louis X's daughter Joan of Navarre had had a son, Charles.
Edward continued to use this title until the Treaty of Brétigny on May 8, 1360, when he abandoned his claims in return for substantial lands in France. After the resumption of hostilities between the English and the French in 1369, however, Edward resumed his claim and the title of King of France. His successors also used the title until the Treaty of Troyes on May 21, 1420, in which the English recognised Charles VI as King of France, but with his new son-in-law King Henry V of England as his heir (disinheriting Charles VI's son, the Dauphin Charles). Henry V then adopted the title Heir of France instead.
Henry V and Charles VI died within two months of each other in 1422, and Henry V's infant son (Charles VI's grandson) Henry VI became King of France. He was the only English king who was de facto King of France, rather than using the style as a mere title of pretence. However, by 1429 Charles VII, with the support of Joan of Arc, had been crowned at Reims and begun to push the English out of northern France. In 1435, an end to the French civil war between Burgundians and Armagnacs allowed Charles to return to Paris, and by 1453 the English had been driven out of their last strongholds in Normandy and Guyenne. The only French territory left to the English was Calais, which was held until 1558.
Following an episode of insanity on the part of Henry VI of England, in 1453 and the subsequent outbreak of the Wars of the Roses (1455 - 1487), the English were no longer in any position to pursue their claim to the French throne and lost all their land on the continent, except for Calais.
Calais would know the rule of eight more English Kings and Queens of France until 1558:
Ill feeling between the two nations continued well into the 16th century. Calais was captured by French troops under Francis, Duke of Guise on January 7, 1558. Mary would continue, however, to be styled Queen of France for the rest of her reign, as did her half-sister and successor Elizabeth I, despite her abandonment of her claims to Calais in the Treaty of Cateau-Cambrésis of 1559.
Elizabeth died childless. Her successor was her cousin, James VI of Scotland. The thrones of England and Scotland were joined in a personal union until 1707. The seven monarchs of this period would continue to use the style King/Queen of France. Their claim was however merely nominal. None of them was willing to engage in military campaigns for France against the actual Kings of France Henry IV, Louis XIII and Louis XIV of France. Indeed, Charles I married a sister of Louis XIII, and his son Charles II, spent much of his exile during the Interregnum in France:
The Act of Union 1707 declared the joining of the Kingdom of England with the Kingdom of Scotland to a new Kingdom of Great Britain. The Kingdom would have four Monarchs until 1801. They would also style themselves Queen/King of France. However none of them actually questioned the rights of Louis XIV and his successors Louis XV, Louis XVI, Louis XVII and Louis XVIII:
The Kingdom of France itself had been abolished on September 21, 1792, replaced by the French First Republic. There was no longer a kingdom of France at all, and George III was certainly not its king.
In July 1797, during the peace negotiations at the Conference of Lille, the French delegates demanded that the King of Great Britain abandon the title of King of France as a condition of peace. The negotiations were broken off in November, 1797, so the title was retained for the while.
The Act of Union 1800 declared the joining of the Kingdom of Great Britain with the Kingdom of Ireland to a new United Kingdom of Great Britain and Ireland. George III chose to drop his claim to the French Throne, whereupon the fleur de lis, part of the coat of arms of all claimant Kings of France since the time of Edward III, was also removed from the British royal arms. Britain finally recognised the French Republic by the Treaty of Amiens of 1802.
The change was not acknowledged by then current Jacobite claimant Henry Benedict Stuart. He continued to formally style himself 'King of England, Scotland, France and Ireland' until his death on July 13, 1807, although he was normally called the Cardinal-Duke of York in everyday usage. Since 1807, none of the Stuarts' cognatic heirs of line (descendants of a daughter of Charles I) has ever used any of the these pretended titles.
The Jacobite pretenders were James II of England and his successors, continuing to be styled "Kings of England, Scotland, France, and Ireland" past their deposition in 1689. All four pretenders continued to actively claim the title King of France as well as that of King of England, Scotland and Ireland from 1689 till 1807:
Several of these pretenders, notably James II for the last 12 years of his life and his son, the Old Pretender, until the Treaty of Utrecht in 1713, were actually pensioners of Louis XIV at the very time they were claiming his title.
The Jacobite succession has continued since 1807 but none of eight recent pretenders has actively pursued his/her claims. They continue to be customarily known as "King (or Queen) of France" by the tiny number of Jacobites.
In addition two failed claimants to the throne of England were also styled King of France. They are usually omitted from regnal lists.
The coat of arms of the Dominion of Canada contains the French fleur-de-lis, which was removed from the British sovereign's arms in 1801. This, however, is merely an acknowlegment of the French heritage of Canada, especially of its province of Quebec, and is not an indication of pretense to the French throne.