Bertha f. Old High German beraht, Old Saxon berht 'bright' from Proto-Germanic *berhtaz.

Brabant

Latin

● 1312 Berta (nom) JeanIII p. 21, Bertha (nom) ibid. p. 27

Czech Republic

Latin

● 1349 Perchta (nom) chlumecky 125; 1350 Berchta (nom) ibid. 167; 1358 Perchte (dat) ibid. 222, p. 31

France

Latin

● c823 Berta (nom) irminon-vol2 38, Palatiolum; 1107 Berta (nom) CartStPC XVII; 1135 Berta (abl) clairvaux-12thc 7; 1138x62 Berta (nom) ibid. 66, Bertha (nom) ibid. 66; 1147 Berta (abl) ibid. 15, Bertha (abl) ibid. 14, Berthe (gen) ibid. 17; 1166 Berta (abl) ibid. 130, Berte (gen) ibid. 130; 1179 Berta (abl) ibid. 176; 1301 Berte (nom) MemPic-vol17 p. 218

◑ c823 Bertinga (nom) irminon-vol2 46, Bertla (nom) ibid. 102, Palatiolum

Middle French

◑ 1563 Bertine RegPCC-1 p. 35; 1565 Bertine ibid. p. 133; 1566 Bertine ibid. p. 250; 1567 Bertine ibid. p. 290; 1568 Bertyne ibid. p. 363

Germany

Latin

● 822x875 Berhtah (nom) TradCorb §47, Bertha (nom) ibid. §47; 1076 Bertha (abl) quix-vol1 47; 1322 Berhte (gen) SMM p. 161

Early New High German

● 1409 Berchte (nom) UrkJen2 18

Middle Low German

● 1304 Berthe (nom) BremUrk2 no. 38

Italy

Latin

● 1092 Berta (nom) RCI-Cam1 565; 1100 Berta (nom) ibid. 626; 1261 Perhtam (acc) FRA-XXXL 209; 1285 Berte (gen) Perugia1285 p. 156

◑ 1368 Bertaccia (abl) Livi 221

Latvia

Latin

◑ 1299 Bertheline (nom) RigSB 185

The Netherlands

Latin

● 1254 Berte (gen) GesOIJ-1 p. 294