Herheim's reading of Wagner's impenetrable last work was first staged last year, before half-sisters Eva Wagner-Pasquier, 64, and Katharina Wagner, 31, officially took over the running of the world's oldest and most prestigious summer music festival.
As part of their joint leadership bid, the duo pledged to open up the family archives to independent historians to shed light on Bayreuth's darkest era when Adolf Hitler was a regular visitor and close friend of then festival head, Winifred Wagner.
In many ways, Herheim's "Parsifal" is the artistic pendant to such a venture, tracing the history of Germany from Wagner's own lifetime, through World War I and the Third Reich to post-war Germany and the present day.
Simultaneously, it traces the reception of Wagner's oeuvre in general and "Parsifal" in particular, while also re-telling the original Arthurian legend of the knights of the Holy Grail.
"Parsifal" is probably the most difficult of Wagner's works to stage.
Composed between 1877 and 1882, it is more religious ceremony than opera.
Indeed, Wagner termed it a "Buehnenweihfestspiel", which literally means a stage consecrational festival play, and is a dense, almost impenetrable mix of mysticism, Christianity and Buddhism.
The only work that Wagner composed specifically with the unique acoustics of Bayreuth's Festspielhaus theatre in mind, the composer's widow Cosima forbade it from being performed anywhere else but there for decades after its premiere in 1882.
It was Cosima, too, who introduced the rule that audiences should not applaud at the end of Act I but remain seated in reverential silence, even if only the most dyed-in-the-wool Wagnerians abide by that tradition nowadays.
Herheim's staging, for all its intellectuality, is also a sumptuous visual feast, a magic lantern, full of poetic imagery.
Before the curtain rises, we see Wagner's ivy-covered grave as the prompter's box.
During the prelude, a pantomime is acted out showing the boy Parsifal resisting a final caress from his dying mother Herzeleide.
Her deathbed is set in the garden of Wahnfried, Wagner's home in Bayreuth, and the villa forms the setting for most of the action.
It is a world of morbid eroticism and decay, where the corrupted knights of the Holy Grail are black-winged angels, the evil Klingsor a transvestite in top hat and tails and his Flower Maidens are straight out of a Busby Berkeley musical.
Set designer Heike Scheele also stunningly re-creates the original scenery from the first production in 1882, a smaller replica of Bayreuth's proscenium and the German Bundestag (parliament) in the 1950s.
In the end, Herheim holds up a mirror to the audience itself, literally.
Among the cast, Korean bass Kwangchul Youn was ideal as Gurnemanz, one of the longest roles in opera with crystal clear diction and velvety tone.
British tenor Christopher Ventris is hard to beat in the title role and German baritone Detlef Roth was a worldly wise Amfortas. Only Japanese mezzo Mihoko Fujimura was a little out of her depth as Kundry, shrill and pressed in the vertiginouos high notes, but sounding more comfortable lower down.
Italian maestro, Daniele Gatti, gave a soft-focused reading of Wagner's luminous score, but was loudly booed at the end for his slow tempi.
"Parsifal" rounded off the glitzy premiere week of the 2009 Bayreuth Festival, which continues until August 28 with performances of "Tristan and Isolde", "The Mastersingers of Nuremberg", "Parsifal" and the four-opera "Ring" cycle.
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