Marie became a novice at the
Priory of Lillechurch in
Kent, but later transferred to
Romsey Abbey in
Hampshire. The abbey had been rebuilt by her uncle
Henry of Blois, Bishop of Winchester. It was at Romsey that she became a nun sometime between 1148 and 1155. She was elected Abbess of Romsey in 1155, the year following her father's death and the subsequent ascension to the English throne of Empress Matilda's son
Henry II. About four years later, on 11 October 1159, her brother William died in
Toulouse. As his marriage to
Isabel de Warenne, Countess of Surrey had been childless, Marie, his only surviving sibling, succeeded as the
suo jure Countess of Boulogne. ==Countess of Boulogne==