On today's date in 1882, the first performance of Richard Wagner's new opera "Parsifal" took place at the Bayreuth Festival in Bavaria. In the audience was a 25-year old American named Gustav Kobbé, an ardent opera fan who would go on to write "Kobbé's Complete Opera Book," a standard reference work on the subject still in print today.

But back in 1882, as Kobbé watched the opening scene of "Parsifal," his gaze became fixed on one spot of the painted scenery, depicting a pile of rocks. Was that Wagner's face painted on one of the rocks? Or was that Wagner himself, staring out at the singers on stage?

During the intermission, Kobbé asked others if they had seen what he had, but they just looked at him as if he were crazy. Perhaps the heat of the Bavarian summer had affected the young American's brain, they suggested.

"I was beginning to think that the appearance of Wagner's face was a mirage, resulting from lights behind the scenes," wrote Kobbé. "I mentioned the matter to one of the singers in the cast. He manifested surprise, not at what I had discovered, but at my having discovered it."

The singer told Kobbé that to insure that singers followed his specific directions where to stand and when to move, Wagner had, in fact, been standing on stage amid the painted rocks. To all eyes but Kobbé's, Wagner's craggy, sun-tanned face had blended in perfectly with the painted scenery.