Source: AF. Hildegard, Abbess of Leon. Thierry and wife Hildegarde are from the Ancestral File. Possible error? Hildegarde would be marrying her father's half brother.
Sources: Kraentzler 1474; NEHGR; A. Roots 144A. Roots: N.N. Hitherto unknown daughter of Louis I and Ermengarde. (NEHGR 109:179-182). K. says she was Mathilde de Aquitaine, daughter of Pippin I, King d'Aquitaine and N.N.