The death in 1186 of Henry's fourth son, Geoffrey II, Duke of Brittany, began a new round of disputes, as Henry insisted that he retain the guardianship of the duchy for his unborn grandson Arthur I, Duke of Brittany. Philip, as Henry's liege lord, objected, stating that he should be the rightful guardian until the birth of the child. Philip then raised the issue of his other sister, Alys, Countess of Vexin, and her delayed betrothal to Henry's son Richard I of England, nicknamed Richard the Lionheart.