Brynhildr is a shieldmaiden and a valkyrie in Germanic mythology, where she appears as a main character in the Völsunga saga and some Eddic poems treating the same events.
She was ordered to decide a fight between two kings, Hjalmgunnar and Agnar, and knew that Odin preferred the older king, Hjalmgunnar, yet she decided the battle for Agnar. For this Odin condemned her to live the life of a mortal woman, and imprisoned her in a remote castle behind a wall of shields on top of mount Hindarfjall, where she sleeps in a ring of flames until any man rescues and marries her. The hero Sigurðr Sigmundson, heir to the clan of Völsung and slayer of the dragon Fafnir, entered the castle and awoke Brynhildr by removing her helmet and cutting off her chainmail armour. The two fell in love and Sigurðr proposed to her with the magic ring Andvaranaut. He later betrayed her.