|Died||after 11 March 824|
|Mother||Hildegard of the Vinzgau|
Bertha was raised with her brothers and sisters in the royal household of Charlemagne, who had all of his children educated by tutors.
An offer by Offa of Mercia to arrange a marriage between Bertha and his son, Ecgfrith, led to Charlemagne breaking off diplomatic relations with Mercia in 790, and banning English ships from his ports. Like her sisters, Bertha never formally married; it has been speculated that Charlemagne did not want his daughters married for strategic reasons, fearing political rivalry from their potential husbands.
Bertha was in a long relationship with Angilbert, a court official, which produced three children. During 794-5, Angilbert presented a poem as a court entertainment, praising the beauty and charms of Charlemagne's daughters; Bertha is praised in particular for having critical discernment and appreciation for poetry, which Angilbert points out is a cause for him to be concerned about how she might receive his poem.
Bertha's children with Angilbert were sons Hartnid, about whom little is known, the historian Nithard, Abbott of St. Riquier and a daughter, Bertha who went on to marry Helgaud II, Count of Ponthieu. Angilbert ended his affair with Bertha and entered a monastery, becoming Abbott of St. Riquier, according to a biography written by their son, Nithard. Angilbert remained an important advisor to Charlemagne, however. The children of Bertha and Angilbert were likely educated in Charlemagne's court. Nithard was a distinguished soldier and politician, and acted as an advisor to Charles the Bald of France.
Following the death of Charlemagne, his successor, Louis the Pious, exiled his sisters to the convents that had been left for their inheritance by their father.
- Becher, Matthias. Charlemagne, Yale University Press, 2005 ISBN 9780300107586
- Garver, Valerie Louise (2009). Women and Aristocratic Culture in the Carolingian World. Cornell University Press. p. 42. ISBN 9780801447716.
- Starr, Brian Daniel (2009). Ascent of the Saints. Brian Daniel Starr. p. 175. ISBN 9781449995805.
- Chalmers, Alexander (1815). The General biographical dictionary: containing an historical and critical account of the lives and writings of the most eminent persons in every nation: Vol. 23 (University of Wisconsin - Madison ed.). J. Nichols. p. 199.