 Isabella had five children by the king, including his heir, later Henry III.In 1220, Isabella married Hugh X of Lusignan, Count of La Marche, by whom she had another nine children.Some of Isabella's contemporaries, as well as later writers, claim that Isabella formed a conspiracy against King Louis IX of France in 1241, after being publicly snubbed by his mother, Blanche of Castile, for whom she had a deep-seated hatred.