Isabella, She-Wolf of France, Queen of England, by Alison Weir

Life and (alleged) crimes of a stylish superwoman

But her book cannot but be engrossing because Isabella's career was unquenchably dramatic. The sixth child of Philip IV of France, she was married to the fey, gay Edward II at the age of 12 in 1308. She suffered the insulting presence of his lover Piers Gaveston until that arrogant young man was murdered by the great barons he had encouraged Edward to fleece of lands and wealth.

She then made a successful comeback in her husband's affections, bearing him two sons and two daughters. When another favourite, Hugh Despenser, came to dominate Edward's butterfly mind, she contrived an excuse for returning to France in 1325 and refused to return.

In 1326 she invaded a restive England with the support of the exiled baron Roger Mortimer and a Flemish army. Country and city alike rose to support her. Despenser was condemned to death and Edward forced to abdicate in favour of his 13-year-old son. He was imprisoned in Berkeley Castle, where he disappeared in 1327. Officially, he died, but speculation was rife that he had been poinarded up his fundament (significant insult). Mortimer and Isabella, widely rumoured to be lovers, then dominated England as avaricious regents for nearly four years.

Fond as he was of his mother, Edward III had no intention of being a puppet king. Rising 18 and unable to ignore what was probably Isabella's second pregnancy, he acted swiftly, seizing Mortimer, and committing him (gagged to prevent his bad-mouthing the Queen Mother) to trial for the murder of Edward II. He was convicted and hanged.

The vast wealth that Isabella had hoarded was at last disbursed. She was kindly treated, albeit corralled in seclusion for propriety's sake until she gave birth to, or miscarried, Mortimer's child, and then generously dowered.

Can a case be made out for the rehabilitation of Isabella? Weir comes down firmly on the "yes" side, excusing her undeniable rapacity as due to her being "blinded by love, infatuation or lust" for Mortimer. In an enthralling passage, she forensically examines and is convinced by the fascinating thesis that Isabella had nothing to do with Edward's death because Edward escaped from Berkeley to live as an itinerant hermit for the next ten years or so.

But what lingers from Weir's portrait of this dynamic, famously beautiful woman is not her doubtful innocence but her genius for survival and re-invention, for persuasion and manipulation. She grew into an elder stateswoman, the dignified grandmother of Edward's 13 children. She took to books, astrology and geometry, and became a lay member of the Franciscan order. Always a snappy dresser, in 1358 she was buried in the scarlet-and-yellow satin wedding cloak she had kept all her life, worn over her dun Franciscan habit. In her hands she held a casket holding her wronged husband's heart. If that's not style, I don't know what is.

Christina Hardyment's 'Malory' is published by HarperCollins