Excerpts from Books and Wikipedia
"Wagner had conceived his idea for a cycle of operas, based loosely on the Norse saga's and the medieval German epic poem of the Nibelunglied, 25 years earlier in Zürich, having been forced to leave Germany for his part in the revolutionary uprising in 1849. After long years of exile Wagner was on the brink of financial ruin when, in 1864,' mad' King Ludwig II invited him to Munich. . . . A summer festival is held at Bayreuth every year solely for the performance of Wagner's operas." [Furtado: 1001 Days]