Flagstad, Kirsten, FLAG stad or FLAHG stah, KUR stuhn or KIHSH tuhn (1895-1962), a Norwegian operatic soprano, became famous as an interpreter of the heroines in the operas of Richard Wagner. Previously unknown to American audiences, her 1935 debut as Sieglinde in Die Walkure at the Metropolitan Opera House in New York City was a storybook triumph. Flagstad achieved her greatest fame in the heavier Wagner roles such as Brunnhilde and Isolde. Although a rather passive actress, she overwhelmed audiences with the power and ease of her singing. Flagstad retired from the operatic stage in 1954, but she continued to sing in concerts and to record opera and songs. She became director of the new Norwegian State Opera in 1958. Flagstad was born in Oslo and made her operatic debut there when she was 18 years old.