The immediate practical cause of the rebellion was Henry II's decision to bequeath three castles, which were within the realm of the Young King's inheritance, to his youngest son, John, as part of the arrangements for John's marriage to the daughter of the Count of Maurienne. At this, Henry the Young King was encouraged to rebel by many aristocrats who saw potential profit and gain in a power transition. His mother Eleanor had been feuding with her husband, and she joined the cause as did many others upset by Henry's possible involvement in the murder of Archbishop Thomas Becket in 1170, which had left Henry alienated throughout Christendom.