It is hard to believe that for decades Karol Szymanowski's masterpiece, his magnificent opera, King Roger of 1926, led such a shadowy existence until it was revealed for what it is by powerful champions such as Simon Rattle: one of the finest operas of the 20th century. The visually strong production by David Pountney provided the Bregenz Festival with one of its most abiding successes in recent years. Scott Hendricks in the baritone title role and Olga Pasichnyk as his Queen, Roxana, were both enthusiastically applauded.