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Dictionary of Medieval Names
from European Sources

Giselhar m. Old High German gīsal 'pledge, hostage' + Old High German heri 'host, army'.

France
Latin
c823 Gisleharius (nom) irminon-vol2 51
Cite as: S.L. Uckelman. "Giselhar". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 2. http://dmnes.org/2016/2/name/Giselhar.