General Notes

Many sources have Adele as mother of Hugues/Hugh II Comte de Ponthieu.  However this is impossible if she married Enguerrand in or after 1033 when her first husband Baudouin Comte de Boulogne died.  There is some doubt as to the sequence of events as the following excerpt of a post to SGM, 14 Nov 1998, by Leo van de Pas, illustrates:

According to Genealogie der Graven van Holland, by Dr. AWE Dek, page 12.  Arnulf 'may' have had a daughter named Aleida,and this Aleida was married to Engelram I Count of Pontieu who died circa 1045. As footnote this books refers to: For this family see C. Brunel, Recueil des Actes des comtes de Ponthieu, Paris 1930.

Now comes the interesting bit, Schwennicke Volume III/4 page 635.  Enguerrand I de Ponthieu married Adeliva, widow of Baudouin Comte de Boulogne, and Adeliva is POSSIBLY daughter of Arnulf van Friesland. That sounds positive until you get hold of page 621 of the same book, the page covering the Counts of Boulogne. There is no mention of a Baudouin/Balduin who married an Adeliva........