The only creditable reference to Hilduin I was when Philip I, King of France, donated the village of Bagneux to the Abbey of Saint-Germain-des-Prés in exchange for Combs la Ville by charter dated 1061, which recounts that Hugh the Great had granted Combs to Hilduino…comiti de Monte qui vocatur Desiderius, who died before his benefactor (before 956), and that Henry I, King of France, had regranted Combs to Manasses nepos supradicti Hilduini comitis [Manasses, grandson of Hilduin] just as suus avunculus Hilduinus [his uncle Hilduin] had held it, noting that Odo comes filius prefati Manassetis [Odo, son of Manasses] now claimed the property.
We cannot resolve these competing claims and will assume that Hilduin was married to Hersende (Heldwide).
In 948, the first church in Montdidier, Somme, was built near the castle of Charlemagne by Hersende.
A common mistake is to assume the Hugh I, Count of Ponthieu, husband of Gisele, daughter of Hugh Capet, was the son of Hilduin I, when, in fact, his father was Hilduin (Herluin), Count of Montreuil, as discussed by Flodoard.
Tardif, J., Monuments historiques, Paris, 1866 Fanning, Steven and Bachrach, Bernard S. (translators), The Annals of Flodoard of Reims, 919-966.