The Manual of Dhuoda records the marriage "anno XI domino nostro Ludoico VIII Kal Iul" at "Aquisgrani palatio" of Doda and Bernard. The Manual was written in 843 and consists of her instructions to her son. 1
Marriage Information:
Duoda married Bernard I, comte d' Autun et d' Auvergne, son of Guillaume, comte de Toulouse, Marquis de Septimanie and Kunégonde d' Austrasie, on 24 Jun 824 in Aix-La-Chapelle (Aachen). (Bernard I, comte d' Autun was born about 795 in Autun, Saone-et-Loire, Bourgogne, France and died between Jan 844 and Jun 844 in Toulouse, Haute-Garonne, Midi-Pyrenees, France.)
Sources
1 Foundation for Medieval Genealogy, Medlands: Bernard.