Фонтевро
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. In 1244, after the plot had failed, Isabella was accused of attempting to poison the king. To avoid arrest, she sought refuge in Fontevraud Abbey, where she died two years later, but none of this can be confirmed.