Bertha

Originally a short form of Germanic names beginning with the Old Frankish or Old Saxon element berht, Old High German beraht meaning "bright" (Proto-Germanic *berhtaz). This was the name of a few early saints, including a 6th-century Frankish princess who married and eventually converted King Æþelbeorht of Kent. It was also borne by the mother of Charlemagne in the 8th century (also called Bertrada), and it was popularized in England by the Normans. It died out as an English name after the Middle Ages, but was revived in the 19th century.

This name also appears in southern Germanic legends (often spelled Perchta or Berchta) belonging to a goddess of animals and weaving.