He has/had a relationship with Adeltrude?.
Child(ren):
http://sbaldw.home.mindspring.com/hproject/prov/lotha000.htm
This Witbert appears in a document from the monastery of Tournus from 28 January 870, in which he donated for the absolution of his lord king Lothair and of his father Lambert and mother Rotrude ["Ego Vuitbertus misericordia Dei comes, cogitans humanae conditionis casum et spem habens, sanctae genitricis Dei et almi confessoris sui Filiberti intercessione a peccatorum posse contagio liberari, sive pro absolutione domni et senioris mei Hlotharii regis, qui mihi et pater extitit et bona quaeque mercede sua largitus est, qui etiam mihi fundum Rodonionem inter caetera contulit, seu etiam pro liberatione Lanberti genitoris mei necnon et Rutrudis genitricis meae et mea, ..." Hlawitschka (1969), 369, n. 10].
Moreover, Witbert appears to have had a similar relationship with Lothair's son Hugues (although poorly repaid), if, as seems probable, he can be identified with the Wicbert who was killed by Hugues in 883 ["Hoc etiam tempore idem Hugo Wicbertum comitem, qui ab ineunte aetate sibi faverat, interfecit; ..." Regino, Chronicon, s.a. 883, 121].
While Hlawitschka's case for identifying count Witbert's mother Rothrude with the daughter of Lothair I is good, his attempt to identify Witbert's father Lambert with Lambert II, count of Nantes, who died in 852, while possible, is less secure.
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