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:  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). Henry II of England:  He became actively involved by the age of 14 in his mother's efforts to claim the throne of England, then occupied by Stephen of Blois, and was made Duke of Normandy at 17. Henry II of England:  He inherited Anjou in 1151 and shortly afterwards married Eleanor of Aquitaine, whose marriage to Louis VII of France had recently been annulled. Henry II of England:  Stephen agreed to a peace treaty after Henry's military expedition to England in 1153, and Henry inherited the kingdom on Stephen's death a year later.
1153