Eustace I was allied to the house of Normandy. This was through the marriage of his son Eustace II to Goda, niece of Richard II. Under Eustace I the counts of Boulogne rose to great prominence in Northern France. He was apparently a patron of Samer Abbey near Calais and he is said to have been buried there. In 1028 Eustace I confirmed the foundation of a college of canons at his castle at Lens Eustace I died in 1049.