Isambert m. Old Saxon, Old High German īsarn 'iron' + Old High German beraht, Old Saxon berht 'bright' from Proto-Germanic *berhtaz.

France

Latin

● c823 Isembertus (nom) irminon-vol2 19, Ved; 1030 Isimbardus (nom) StVdM-II 682; 1032x1064 Isembertus (nom) LDS LV; 1032x1100 Isembertum (acc) ibid. LXV; 1047 Isemberti (gen) CartNDSaintes II; 1067 Isembertus (nom) ibid. XII, Isenbardus (nom) ibid. XII; 1131 Isemberto (abl) ibid. XXII; 1179 Ysembardo (abl) clairvaux-12thc 181; 1261 Ysembardus (nom) ArrestReg-volI IX, BMV

Old French

● 1292 Ysambart (obl) HistHdVParis p. 113; 1296 Yzambart paris1296 p. 25, Yzambert ibid. p. 25; 1307 Ysambars (nom) ArchReimsII1 LX; 1313 Isambart Paris1313 p. 17, Ysambart ibid. p. 151, Ysembart ibid. p. 76

Middle French

● 1392 Ysembert MemBret-II col. 605; 1418 Ysambert HGParis p. 379, Ysembert DdB1418 p. 204; 1421 Ysambart favier 523

Italy

Latin

● 1310 Ysembardus (nom) MonRav-2 CCCL