What 9th-century German composer conceived and promoted the idea of a special festival to showcase his own works, in particular his monumental cycle that is an opera in three acts that is loosely based on "Parzival" by Wolfram von Eschenbach?
Parsifal:  It is loosely based on "Parzival" by Wolfram von Eschenbach, a 13th-century epic poem of the Arthurian knight Parzival (Percival) and his quest for the Holy Grail (12th century).
i don't know