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 .
During the minority of Baldwin IV , Count of Flanders , Eustace 's grandfather , Arnulf III , Count of Boulogne , broke free of control by the count of Flanders .