Dictionary of Medieval Names
from European Sources

Bertmar m. Old High German beraht, Old Saxon berht 'bright' from Proto-Germanic *berhtaz + Old English mære, Old High German, Old Saxon māri from Proto-Germanic *mērijaz 'famous'.

France
Latin
814 Bertemarus (nom) StVdM-II B1
Cite as: A. Brown, S.L. Uckelman. "Bertmar". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2020, no. 1. http://dmnes.org/2020/1/name/Bertmar.