Some of Isabella's contemporaries, as well as later writers, claim that she formed a conspiracy against King Louis IX of France in 1241, after being publicly snubbed by his mother, Blanche of Castile, for whom she harbored a deep-seated hatred.

As a result of John's temerity in taking her as his second wife, King Philip II of France confiscated all of their French lands and armed conflict ensued.

At the time of her marriage to John, the blonde-haired blue-eyed Isabella was already renowned by some for her beauty[7] and has sometimes been called the Helen of the Middle Ages by historians.

[11] The following July, less than a year after his crowning as King Henry III of England, she left him in the care of his regent, William Marshal, 1st Earl of Pembroke, and returned to France to assume control of her inheritance of Angoulême.

It had been previously arranged that her eldest daughter Joan should marry Hugh, and the little girl was being brought up at the Lusignan court in preparation for her marriage.

Isabella was granted the stannaries in Devon, and the revenue of Aylesbury for a period of four years, in compensation for her confiscated dower lands in Normandy, as well as the £3,000 arrears for her pension.

[15] In 1241, when Isabella and Hugh were summoned to the French court to swear fealty to King Louis IX of France's brother, Alphonse, who had been invested as Count of Poitou, their mother, Queen Dowager Blanche openly snubbed her.

This so infuriated Isabella, who had a deep-seated hatred of Blanche for having fervently supported the French invasion of England during the First Barons' War in May 1216, that she began to conspire actively against King Louis.

Isabella and her husband, along with other disgruntled nobles, including her son-in-law Count Raymond VII of Toulouse, sought to create an English-backed confederacy which united the provinces of the south and west against the French king.

On a visit to Fontevraud, her son King Henry III of England was shocked to find her buried outside the abbey and ordered her immediately moved inside.

[18] She was played by actress Zena Walker in the TV series The Adventures of Robin Hood episode "Isabella" (1956), before her marriage to John, but not as a 12-year-old.