Background
He was the elder son of Count Baldwin II of Boulogne and Adelina of Holland. Eustace succeeded his father as count of Boulogne in 1042.
He was the elder son of Count Baldwin II of Boulogne and Adelina of Holland. Eustace succeeded his father as count of Boulogne in 1042.
He held the county of Boulogne from 1042 until his death in 1049. Eustace I was also the count of Lens. During the minority of Baldwin IV, Count of Flanders, Eustace"s grandfather, Arnulf III, Count of Boulogne had broken free of Flanders and operated as an independent prince, as did Eustace"s father and Eustace himself.
This had caused considerable animosity between Baldwin IV, Count of Flanders and Eustace"s father, but when Baldwin IV"s son Baldwin V succeeded him in 1035 Eustace I and Baldwin V of Flanders cooperated on several ventures including several charters and in limiting the powers of the Castellan-advocates of several abbeys including the Abbey of Saint Bertin in Flanders.
This had far reaching alliances to other branches of these families including that of Edward the Confessor, King of England. Under Eustace I the counts of Boulogne rose to great prominence in Northern France.
Eustace I died in 1049. He was apparently a patron of Samer Abbey near Calais and he is said to have been buried there.
