Remarks:
Count of Boulogne. There is disagreement about his parentage. His father may have been Baldwin II de Boulogne, or, alternatively, Ernicule de Boulogne. These are not different names for the same person, but alternative solutions to his parentage. Likewise the placement of Adele of Ghent as the mother of Eustache is not well supported, and the use of Ghent as a toponym by the counts of West Friesland is probably wrong.