Queen Isabella, also known as Isabella of France, as well as the "She-Wolf of France" in her later years, married the future Edward II at a young age (she was 16). The marriage was arranged in the interest of politics by Edward I; hence it is not surprising that the couple was not happy, to say the least.

Edward II was purportedly homosexual, and he spent most of his time with Piers Gaveston and then the Despensers, so Queen Isabella grew resentful. She did bear her husband a son, the future Edward III, but one has to wonder if Edward II's nobles and subjects believed that the child was his. However, Braveheart's depiction of William Wallace being Edward III's father is impossible, for it is quite unlikely that Wallace and Isabella ever met. Additionally, I have seen no speculation or opinion indicating that Edward III was not of Edward II's line. Edward II and Isabella were married in 1308, three years after Wallace's death, and the future Edward III was born in 1312, seven years after Wallace's execution.

As Edward II's grip on the crown grew weaker and his nobles grew more and more dissatisfied, Isabella became further alienated from her husband. She eventually fled to France for protection, taking her son the prince with her. It was only when her husband was at his lowest point with his nobles that Isabella and Roger Mortimer invaded England and captured Edward, in 1327. Edward II was held prisoner for some months but was then murdered, his wife very likely having a role in his death. Isabella retained some power for a time after her husband's death, but the nobles soon grew tired of her and her lover, Mortimer, and she sank into the background once her son was crowned Edward III.

Tratto da: http://bay1.bjt.net/~melanie/brave.html#Will_Wall