Valkyries are attested in the 13th-century Eddas, and several other works of the same century, based on earlier oral sources.
The most prominent valkyrie in literature is Brunhild.
Valkyrie in "The Catcher in the Rhine"Edit
Brunhild the valkyrie was cursed to slumber in a castle surrounded by flame until some brave soul entered the castle and awoke her with a kiss. The man who came to do this turned out to be less than ideal.
Valkyrie in "The Old Grind"Edit
The valkyries descended onto the field of the Siege of Chartres, to gather the souls of dead vikings to bring home to Valhalla. Their father King Odin accompanied them on this mission. Due to his bad eyesight, the king gathered a living giantess, Fenia of Orkney, mistaking her for another valkyrie.