Petronilla of Aquitaine, (circa 1125 -- 1153) born the daughter of William X of Aquitaine and Aenor of Châtellerault . She was the sister of Eleanor of Aquitaine, who was Queen of France and England. She is variously called Alix and Petronille; she typically went by Alix after her marriage, while Petronille seems to have been her childhood name (she is referred to as such in her father's will).

Petronille accompanied her sister to the French court, where she met the very-married Count Raoul I of Vermandois , a cousin to the King of France. He repudiated his wife and married her, and they were excommunicated by the Pope. King Louis VII of France was enraged, and sent his brother to invade their lands. Pope Innocent II promised to lift the excommunication, but recanted his promise in 1143. Hostilities flared, and King Louis infamously burned Vitry trying to punish his sister-in-law and cousin. Finally the Pope died and his successor lifted the excommunication at Council of Reims in 1144. However, Petronille and Raoul divorced in 1151, as he remarried the next year. Petronille died in 1153, leaving two children:

1. Elizabeth (Mabile) de Vermandois (1143-1183), married Count Philip of Flanders
2. Raoul II of Vermandois (1147-1167), died of leprosy

Sources

• Kerrebrouck, Patrick van. Les Capétiens 987-1328, 2000