Dictionary of Medieval Names
from European Sources

Frotberga f. Old Frisian, Old Saxon frōd, Old High German fruot 'wise' + Old High German berg 'mountain, hill'.

France
Latin
c823 Frotberga (nom) irminon-vol2 21, Wan
Cite as: S.L. Uckelman. "Frotberga". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Frotberga.