The Norwegian dramatic soprano, often called “the voice of the century,” was born 115 years ago today. The hard-working singer became a sensation “overnight” when, after the first act of her Met debut as Sieglinde, she was hailed by intermission commentator Geraldine Farrar as a new star.

To celebrate Mme. Flagstad’s birthday, an act from one of her greatest roles in what may be its finest performance ever: the first act of Tristan und Isolde from Covent Garden in the spring of 1937.

Tristan und Isolde, Act I

Tristan: Lauritz Melchior
Isolde: Kirsten Flagstad
Brangäne: Karin Branzell
Kurwenal: Paul Schöffler
Ein Seemann: Parry Jones
The Royal Opera House, Covent Garden, London; June 22, 1937. Conductor: Thomas Beecham.