Bayreuth Festival the world of opera. Other notable directors to have participated in "Werkstatt Bayreuth" included Jean-Pierre Ponnelle, Sir Peter Hall of the Royal Shakespeare Company, Götz Friedrich of the Deutsche Oper Berlin, Harry Kupfer of the Berlin State Opera in the former communist East Germany and Heiner Müller of the Berliner Ensemble. In the end, Wolfgang's decision to bring in experimental directors helped rejuvenate Bayreuth and restore its reputation as the world leader in Wagnerian opera. There was uncertainty over how the Festival was to be managed after the retirement of Wolfgang Wagner at the end of August 2008. In 2001,
Bayreuth Festival banned her from administration of the Bayreuth Festival and its assets, which fell eventually to her two sons, Wolfgang and Wieland. During American occupation of the region after World War II, the theatre was used for army recreation and religious services for American soldiers. Only popular concerts and mixed entertainment were allowed: comedy, dancing, acrobatics, and then only "Die Fledermaus" was staged. When the Festival House was handed over to the city of Bayreuth in 1946, it was used for concerts of the Bayreuth Symphony Orchestra and the performances of such operas as "Fidelio", "Tiefland", "Madama Butterfly" and "La traviata".