Hildtrude of Bavaria

Hiltrud (Bavaria) from de.Wikipedia "Hiltrud (Bayern)", translated:

Hiltrud (* 715 ; † 754 ), Duchess of Bavaria, was a daughter of Karl Martell and his first wife Chrotrud.

At her father's court, she developed an intense relationship with Duke Odilo of Bavaria, which has led to a scandal.[1] After the death of her father (741), she fled to Regensburg on the advice of her stepmother Swanahild, the daughter of Theodos II, where she married Odilo that same year. With him she had a son, the later Duke Tassilo III. Presumably from 748, the death of Odilo, she exercised guardianship over the still underage son. Salzburg, one of the residence cities of the Agilulfinger family, is assumed to be their whereabouts. Here she was also the third abbess of Nonnberg Monastery.[2]

1. Herwig Wolfram: Tassilo III. Höchster Fürst und niedrigster Mönch, S. 20. Verlag Friedrich Pustet, Regensburg 2016, ISBN 978-3-7917-2792-9.
2. Herwig Wolfram: Tassilo III. Höchster Fürst und niedrigster Mönch, S. 22f. Verlag Friedrich Pustet, Regensburg 2016, ISBN 978-3-7917-2792-9.

Hammer, Carl I. From Ducatus to Regnum Ruling Bavaria Under the Merovingians and Early Carolingians. Brepols, 2007. ISBN: 9782503525822. Google Books Snippet View Only. — Note: This book may be available at a research library near you: Worldcat.org. It is an Illustrated edition, and it's an expensive 380-page book.

Fried, Johannes. “The Warrior King.” Charlemagne, translated by Peter Lewis, Kindle Illustrated ed., Harvard University Press, 2016, pp. 91–163, Google Books.