In what year did Henry I of Castile's grandather sign a peace treaty guaranteeing his successorship to the throne of England?
Henry I of Castile Henry I of Castile (14 April 1204 – 6 June 1217) was king of Castile. He was the son of Alfonso VIII of Castile and Eleanor of England, Queen of Castile (daughter of Henry II of England and Eleanor of Aquitaine).
Dual monarchy of England and France The dual monarchy of England and France existed during the latter phase of the Hundred Years' War when Charles VII of France and Henry VI of England disputed the succession to the throne of France. It commenced on 21 October 1422 upon the death of King Charles VI of France, who had signed the Treaty of Troyes which gave the French crown to his son-in-law Henry V of England and Henry's heirs. It excluded King Charles's son, the Dauphin Charles, who by right of primogeniture was the heir to the Kingdom of France. Although the Treaty was ratified by the Estates-General of France, the act was a contravention of the French law of succession which decreed that the French crown could not be alienated. Henry VI, son of Henry V, became king of both England and France and was recognized only by the English and Burgundians until 1435 as King Henry II of France. He was crowned King of France on 16 December 1431.