Hohenstaufen Origins

In ES (Freytag von Loringhoven) Volume 1 Tafel 5 (published 1975)
We find Friedrich von Bueren died before 1094, married Hildegard von =
Schwaben, daughter of Otto, Duke of Schwaben. They married around/before =
1050 as they had (six) children in the 1050s

In the same volume Tafel 8=20
we find Otto (died in 1057), Markgraf von Schweinfurt, Duke of Schwaben, =
with five daughters : Eilika, Judith, Beatrix, Gisela and Bertha =
(Alberada).-----no Hildegard =20

Peter Stewart...

Yes, no-one knows for certain.

The ES table of 1975 apparently relied on Emil Kimpen's Ezzonen und
Hezeliniden in der rheinischen Pfalzgrafschaft, _Mitteilungen des
Österreichischen Instituts für Geschichtsforschung_, Ergänzungsband 12
(1933), making Hildegard a daughter of Otto II, duke of Swabia.

Other conjectures make her a daughter of Hugo V of Egisheim, count of
Dagsburg or of Richwin, count of Mömpelgard (Montbéliard) whose wife may
have been Hildegard of Egisheim.

The genealogie-mittelalter website followed Hansmartin Decker-Hauff in
making Hildegard a daughter of Louis II, count in the Sundgau, of Mousson &
Ferrette by Sophie of Lorraine, countess of Bar. There is no direct evidence
for this either, as far as I know.

ES (1997) took a sensible course in leaving the family background of
Friedrich's wife blank. However, from memory her name was recorded as
Hildegard.

Peter Stewart