collaborations with Schubert. This version of the opera was a great success, and Fidelio has been part of the operatic repertory ever since. Although critics have noted the similarity in plot with Gluck's opera Orfeo ed Euridice—the underground rescue mission in which the protagonist must control, or conceal, his emotions in order to retrieve his or her spouse, we do not know whether or not Beethoven or any of the librettists had this in mind while constructing the opera. No other work of Beethoven caused him so much frustration and disappointment. He found the difficulties posed by writing and producing an opera so disagreeable, he never attempted to compose another. In a letter to Treitschke he said, "I assure you, dear Treitschke, that this opera will win me a martyr's crown. You have by your co-operation saved what is best from the shipwreck. For all this I shall be eternally grateful to you." The full score was not published until 1826, and all three versions are known as Beethoven's Opus 72. The first performance outside Vienna took place in Prague on 21 November 1814, with a revival in Vienna on 3 November 1822. In its two-act version, the opera was staged in London on 18 May 1832 at the King's Theatre, and in New York on 9 September 1839 at the Park Theatre. 20th-century performance history Fidelio was Arturo Toscanini's first complete opera performance to be broadcast on radio in the United States, over the NBC radio network, in December 1944, by the NBC Symphony Orchestra, featuring soloists Rose Bampton and Jan Peerce (though a shortwave broadcast of one act, conducted by Toscanini, had earlier been relayed from a 16 August 1936 performance at Salzburg). Divided into two consecutive broadcasts, the 1944 performances were later issued by RCA Victor on LP and CD. Fidelio was the first opera performed in Berlin after the end of World War II, with the Deutsche Oper staging it under the baton of Robert Heger at the only undamaged theatre, the Theater des Westens, in September 1945. At the time, Thomas Mann remarked: "What amount of apathy was needed [by musicians and audiences] to listen to Fidelio in Himmler's Germany without covering their faces and rushing out of the hall!" Not long after the end of World War II and the fall of Nazism, conductor Wilhelm Furtwängler remarked in Salzburg in 1948: [T]he conjugal love