I Originally had Hildegarde de Flanders m. Wichman, Count de Gand, and their daughter Hildegarde de Gand m. Dietrich. According to sources quoted by Curt, below, Hildegarde de Gand & Hildegarde de Flanders are one and the same person. I left the marriage to Wichman as a 1st husband; her marriage to Dietrich seems somewhat late, and possibly she had a 1st husband.
Curt Hofemann, curt_hofemann@@yahoo.com, writes in a post-em:
Hi Jim,
ES II:5 lists b. ca 934.
ES II:2, 5 lists d. 10 Apr 990 & Moriarty lists 990.
ES II:2 makes her the daughter of Arnold I Count of Flanders (not granddaughter).
Moriarty p55 "perhaps dau of Arnulf I Count of Flanders"
Todd A. Farmerie <farmerie@@interfold.com> in a message to Gen-Medieval 13 Mar 2001: mother unk, not Adele of Vermandois
A somewhat new, very worthwhile website by Stewart Baldwin is the Henry Project at:
http://sbaldw.home.mindspring.com/hproject/henry.htm
which states:
No direct evidence is known for the suggestion that Hildegard was Arnulf's daughter. However, the onomastic evidence for such an affiliation is strong, given that Hildegard had sons named Arnulf and Egbert, the latter of which is an Anglo-Saxon name that had only been recently introduced into the family of Flemish counts through Arnulf's mother. However, chronological considerations make it highly unlikely that Hildegard was born late enough to be a daughter of Adele of Vermandois. Since the chronology leaves plenty of room for an earlier marriage of Arnulf (who was probably in his 40's when he married Adele), it is most likely that Hildegard was born to an earlier marriage. [Ref: Erich Brandenburg, Die Nachkommen Karls des GroÆen, Frankfurt, 1964, 91-2; = Karl Ferdinand Werner, 'Die Nachkommen Karls des GroÆen bis um das Jahr 1000 (1.-8. Generation)', Karl der GroÆe 4 (1967), 69-70