Research Notes:

The Genealogica comitum Buloniensium records that "Karolus dux" was father of "Ermengardem et Gerbergam", and that "Gerberga soror Ermengardis" was mother of "Henricum seniorem de Bursella". The Gesta Abbatem Trudonensium names "Gerbergam, filiam Karoli ducis Lotharingie" as wife of "Lambertus filius Reyneri comitis Montensis", specifying that Brabant (including Louvain and Brussels) was her dowry. The Annales Hanoniæ name "Gebergam filiam Karoli ducis Lotharingie" as wife of "Lambertus…comes Lovaniensis". "Gerberga" is named as wife of "Lantbertum comitem, filium Ragineri Longicolli" in the Gesta of Gembloux Abbey when recording her husband's death, but her origin is not stated. Sigebert's Chronica records in 977 that "Lantbertus" married "Gerbergam filiam Karoli ducis", but this date must be incorrect. Richer records that "Karolum…cum uxore Adelaide et filio Ludovico, et filiabus duabus, quarum altera Gerberga, altera Adelaidis dicebatur, necnon et Arnulfo nepote" were imprisoned. This suggests that Gerberga was not yet married at that date. The birth date of Gerberga is estimated on the basis of the likely birth date ranges of two of her presumed children by Comte Lambert. ²