Robert's father is shown as Heribert II in the Flodoard Annales. In the same source, his mother is listed as a sister of Hugues the Great, and thus a daughter of Robert I ["... Hugo dux cum nepotibus suis, Heriberti filiis, ... inter filios Heriberti comitis ..., Hugone principe avunculo ipsorum ... Nepotes Hugonis, Heribertus et Rotbertus, ..."]. Since the sons of Heribert were nepotes of Hugues, and Hugues was avunculus to the sons of Heribert, the clear interpretation is that Heribert was married to a sister of Hugues, and the names of Eudes, Hugues and Robert given to three of the sons of Heribert provide further confirmation. There is not clear documentation for her name. It is assumed her name was Liégarde because of the appearance of that name among her children and in the necrology of Saint-Quentin who would probably be connected somehow to the counts of Vermandois. There is no evidence for the name Hildebrandte, and the references to the name Adele, probably refer to the wife of Robert I.