Marie I, Countess of Boulogne

Marie I
Coat of arms of the county of Boulogne
Countess of Boulogne
Reign	11 October 1159–1170
Predecessor	William I
Successor	Matthew
Born	1136
Died	25 July 1182 (aged c. 46) St Austrebert, Montreuil
Burial	St Austrebert
Spouse	Matthew of Alsace m. 1160; div. 1170
Issue	Ida, Countess of Boulogne Matilda, Duchess of Brabant
House	House of Blois
Father	Stephen, King of England
Mother	Matilda I, Countess of Boulogne

Marie I or Mary (1136 – 25 July 1182 in St Austrebert, Montreuil, France) was the suo jure Countess of Boulogne from 1159 to 1170. She also held the post of Abbess of Romsey for five years until her abduction by Matthew of Alsace, who forced her to marry him.

Marie was the youngest daughter of King Stephen of England and his wife Matilda I, Countess of Boulogne. She was born in 1136, one year after her father had succeeded to the English throne. His reign was to be marked by the civil war known as "The Anarchy" during which he fought a series of battles to retain the crown which was claimed by his double first cousin Empress Matilda.

She had three brothers, Eustace, William, Baldwin, and one sister, Matilda. She also had three illegitimate half-siblings by her father's relationship with a Norman lady known only as Dameta. She 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. Her brother William had been passed over in the succession.

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.