The Annales Stadenses name "Hildigardam" as wife of "Heinricus calvus" and mother of "Bonus Heinricus". The primary source which confirms her parentage has not yet been identified. 1
Marriage Information:
Hildegarde married Heinrich I "der Kahle", graf von Stade, son of Lothar II, graf von Stade and Swanhilde, after 973. (Heinrich I "der Kahle", graf von Stade died on 11 May 976.)
Sources
1 Foundations for Medieval Genealogy, Medlands, Hildegard.