Original: The story of the eponymous character is taken from medieval German romance , notably the Parzival of Wolfram von Eschenbach and its sequel , Lohengrin , written by a different author , itself inspired by the epic of Garin le Loherain .
Simplified: Liszt chose to conduct it on that particular day because 28 August was the birthday of Johann Wolfgang von Goethe who had lived in Weimar .