Stewart Baldwin: http://sbaldw.home.mindspring.com/hproject/prov/lotha000.htm

Rotrude, baptized in Pavia, 835×840; probably m. Lambert, count, possibly the same person as Lambert II, d. 852, count of Nantes.

• The only explicit information about Rotrude is that she was baptized at Pavia while her parents were there ["... et suscepit filiam praedicti augusti nomine Rotrudam, ..." Agnellus, Liber pontificalis ecclesiae Ravennatis, c. 171, MGH SRL, 388; Hlawitschka places this between 835 and 840, Hlawitschka (1969), 367].
• As Hlawitschka has shown, Rotrude can be identified with a high degree of probability with the Rotrude who was wife of a certain Lambert and mother of a count Witbert.
• 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].
• Not only does Witbert speak of Lothair's generosity toward him, but more importantly, he states that Lothair was like a father to him ("qui mihi et pater extitit").
• 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. For earlier conjectures on the identiy of Rotrude's husband, see the Commentary section.

http://fmg.ac/Projects/MedLands/LOTHARINGIA.htm#_Toc260754300

ROTRUDE (chr Pavia [835/40]-). The baptism of Rotrudis daughter of Lothaire is recorded at Pavia in [835/40][75]. [same person as…? ROTRUDE . "Witbertus…comes" donated property at Ornois to the abbey of Tournus, for the souls of "Lanberti genitoris mei necnon et Rutrudis genetricis meæ", by charter dated 28 Jan 870[76]. Hlawitschka suggests that she was the daughter of Emperor Lothaire I, as her son's charter dated 28 Jan 870 records that the property he donated to the abbey of Tournus had been granted to his father by Emperor Lothaire[77]. However, the copy of the charter reproduced in the Histoire de Tournus, cited above, states that the property had been donated to Wicbert by "senioris mei Hlotharii Regis". m ([850/51]) LAMBERT Comte et Marquis de Nantes, son of LAMBERT [I] Comte et Marquis de Nantes [Guidonen] & his wife [--- of Italy] (-killed in battle 1 May 852).]

[75] Settipani (1993), p. 265 footnote 504, citing Agnellus Liber pontificalis ecclesiæ Ravennatis c. 171, MGH SRL, p. 388 (without specifying the volume).

[76] Chifflet, P. F. (1644) Histoire de l´abbaye royale et de la ville de Tournus (Dijon), Preuves, p. 212.

[77] Settipani (1993), p. 265, citing Hlawitschka, E. 'Waren die Kaiser Wido und Lambert Nachkommen Karls des Grossen?', Quellen und Forschungen aus italienischen Archiven und Bibliotheken 49 (1969), pp. 366-86.

-------------------- Rotrude, baptized in Pavia,Italy; probably m. Lambert, count, possibly the same person as Lambert II, d. 852, count of Nantes. The only explicit information about Rotrude is that she was baptized at Pavia while her parents were there; Hlawitschka places this between 835 and 840.

Rotrude can be identified with a high degree of probability with the Rotrude who was wife of a certain Lambert and mother of a count Witbert.