""The Wibelungen"" is a four-part opera written by the German composer Richard Wagner. It is based on a medieval German epic poem called ""Nibelungenlied"" and tells the story of Siegfried, a hero who slays a dragon and wins the love of the beautiful Valkyrie, Br�����nnhilde. However, their love is doomed as Siegfried is betrayed and killed by his own half-brother, Hagen. Br�����nnhilde,...