"Kirsten Flagstad was greatest Wagnerian soprano of the mid-20th century. She came from a family of professional musicians and studied singing in Oslo, where, after her operatic debut there in 1913, she worked principally as a light soprano, singing oratorio, opera, and operetta. In 1928 she joined the Storm Theatre in Gothenburg, Sweden, and added further operatic roles to her repertory." - Encyclopedia Brittanica