Dictionary of Medieval Names
from European Sources

Casimir m. Proto-Slavic *kaziti, meaning uncertain, + Slavic měr 'prestige, fame'.

The name of an 11th C king of Poland, a 12th C king of Poland, a 14th C king of Poland, a 15th C king of Poland, and a 15th C Polish saint.

Germany
Latin
1230 Casimiro (abl) hennes-vol1 p. 89
Ukraine
Latin
1469 Kazimiro (abl) AGZ-18 37
Cite as: S.L. Uckelman. "Casimir". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2017, no. 1. http://dmnes.org/2017/1/name/Casimir.