Original sentence: Alix of Thouars (5 September1201 – October 21 1221) (in Breton Alis) was the nominal Duchess of Brittany from 1203 to her death.Alix's half-brother was Arthur I, Duke of Brittany.In 1206, King Philip II of France annexed Brittany from her father and became  the Regent of the Duchy in Alix’s name.In 1213, the King arranged her marriage to his cousin Peter of Dreux, who became the Regent
Edited sentence: Alix of Thouars (5 September, 1201 – October 21 1221) (in Breton Alis) was the nominal Duchess of Brittany from 1203 to her death.Alix's older half-brother was Arthur I, Duke of Brittany and her half-sister was Eleanor the Fair Maid of Brittany.At the Battle of Mirebeau in 1202, Arthur and Eleanor were captured.Eleanor was imprisoned at Corfe Castle and her brother Arthur was murdered.In 1206, King Philip II of France annexed Brittany from her father and became the Regent of the Duchy in Alix’s name.In 1213, the King arranged her marriage to his cousin Peter of Dreux, who became the regent.The Breton Barons recognized Alix as Duchess of Brittany after the death of her brother Arthur, instead her older sister, perhaps fearing John Lackland's claims to rule Brittany in representation of the imprisoned Eleanor's rights.Upon the death of Richard I of England, a power struggle commenced between her brother Arthur and King John of England.the children of Constance and Geoffrey Plantagenet