Dictionary of Medieval Names
from European Sources

Rhyshoiarn m. Old Welsh rīs 'ardor; fiery warrior' + Old Breton (ho)iarn 'iron'.

France
Latin
833 Rishoiarn (nom) CartRed VIII
Cite as: S.L. Uckelman. "Rhyshoiarn". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2017, no. 1. http://dmnes.org/2017/1/name/Rhyshoiarn.