[2] Adelaide's brother or half-brother, Robert's son and successor William the Conqueror, was likewise illegitimate.
[a] Adelaide's first marriage to Enguerrand II, Count of Ponthieu potentially gave William a powerful ally in upper Normandy.
[3] But at the Council of Reims in 1049, when the marriage of William with Matilda of Flanders was prohibited based on consanguinity, so were those of Eustace II, Count of Boulogne and Enguerrand of Ponthieu, who was already married to Adelaide.
[b][5] As a dowager Adelaide began a semi-religious retirement and became involved with the Abbey of Saint-Martin d'Auchy [fr], presenting them with a number of gifts.
[5] In 1060 she was called upon again to form another marital alliance, this time to a younger man, Odo, Count of Champagne.
[7] In 1082, William and his wife, Matilda, gave to the abbey of the Holy Trinity in Caen the town of Le Homme in the Cotentin with a provision to the Countess of Albamarla (Aumale), his sister, for a life tenancy.