Idomeneo, re di Creta ossia Ilia e Idamante (Italian for "Idomeneus, King of Crete, or, Ilia and Idamante"; usually referred to simply as Idomeneo, K. 366) is an Italian language opera seria by Wolfgang Amadeus Mozart.
 The libretto was adapted by Giambattista Varesco from a French text by Antoine Danchet, which had been set to music by André Campra as "Idoménée" in 1712.
 Mozart and Varesco were commissioned in 1780 by Karl Theodor, Elector of Bavaria for a court carnival.
 He probably chose the subject, though it might have been Mozart.
 The work premiered on 29 January 1781 at the Cuvilliés Theatre in Munich, Germany.
Jay Hunter Morris (born July 3, 1963) is an American operatic tenor.
 He is best known internationally for the role of Siegfried in the Metropolitan Opera's 2011–12 series of Wagner's "Ring Cycle", performances of which were cinecast and radio broadcast live worldwide, aired on U.S. television, and released on DVD.
German submarine "U-4711" was a Type XXIII U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 She was ordered on 7 July 1944, and was laid down on 1 December 1944 at Friedrich Krupp Germaniawerft AG, Kiel, as yard number 953.
 She was launched on 21 February 1945 and commissioned under the command of "Oberleutnant zur See" Siegfried Endler on 21 March 1945.
Siegfried, WWV 86C, is the third of the four music dramas that constitute "Der Ring des Nibelungen" ("The Ring of the Nibelung"), by Richard Wagner.
 It premiered at the Bayreuth Festspielhaus on 16 August 1876, as part of the first complete performance of "The Ring" cycle.
Delores Ziegler (born 4 September 1951) is an American mezzo-soprano who has had an active international performance career since the late 1970s.
 A former resident artist at the Cologne Opera, she has performed leading roles with many of the world's best opera houses, including La Scala, the Lyric Opera of Chicago, the Metropolitan Opera, the San Francisco Opera, and the Vienna State Opera.
 She is currently a professor of voice at the University of Maryland.
 While she has performed a broad repertoire, she is widely admired for her performances in operas by Wolfgang Amadeus Mozart and Richard Strauss; particularly Cherubino in "The Marriage of Figaro", Dorabella in "Così fan tutte", Idamante in "Idomeneo", and Octavian in "Der Rosenkavalier".
On September 26, 2006, the Deutsche Oper Berlin announced the cancellation of four performances of Mozart's opera "Idomeneo, re di Creta", planned for November 2006, citing concerns that the production's depictions of the severed head of the Islamic prophet Muhammad raised an "incalculable security risk."
 "To avoid endangering its audience and employees, the management has decided against repeating "Idomeneo" in November 2006," the opera house said in a press release.
German submarine "U-3018" was a Type XXI U-boat (one of the ""Elektroboote"") of Nazi Germany's "Kriegsmarine", built for service in World War II.
 She was ordered on 6 November 1943, and was laid down on 18 September 1944 at AG Weser, Bremen as yard number 1177.
 She was launched on 9 November 1944, and commissioned under the command of "Oberleutnant zur See" Siegfried Breinlinger, on 7 January 1945.
Giovanni Valesi (born Johann Evangelist Wallishauser, Walleshauser or Wellesberger; pseudonym also spelled Walesi or Vallesi) (28 April 1735, Hattenhofen – 10 January 1816, Munich) was a German tenor.
 In 1756 he entered the service of Duke Clemens Franz at Munich and was sent to Italy for training.
 A court singer at Munich from 1770 to 1798, he took part in the first performances of Mozart's "La finta giardiniera" and "Idomeneo re di Creta".
 Afterwards, he took up teaching.
 His pupils included Johann Valentin Adamberger, Carl Maria von Weber, and his five children, born from his marriage in 1775 to Leni Mindl.
German submarine "U-717" was a Type VIIC U-boat of Nazi Germany's "Kriegsmarine" during World War II.
 The submarine was laid down on 24 April 1942 at the H. C. Stülcken Sohn yard at Hamburg, launched on 20 February 1943, and commissioned on 19 May 1943 under the command of "Oberleutnant zur See" Siegfried von Rothkirch und Panthen.
 Attached to "5th U-boat Flotilla" based at Kiel, "U-717" completed her training period on 31 July 1944 and was assigned to front-line service.
The Stresa Festival Orchestra is a formation composed by young and talented musicians, coming from renewed european orchestras, calling by Gianandrea Noseda to perform every year some original production for the Stresa Festival.
 The debut of the Orchestra, on 26 August 2003 with Mozart’ "Don Giovanni", began the project of the concert performances of different operas: "Così fan tutte" (2004), "Le nozze di Figaro" (2005), "The magic flute" (2006), "La clemenza di Tito" (2007), "The Rake’s progress" (2008), "La Cenerentola" (2009), "Idomeneo" (2010).
 During the years many singers was invited such as Evgenij Akimov, Simone Alberghini, Sergej Alexashkin, Tatiana Borodina, Nicola Beller Carbone, Natale De Carolis, Mariella Devia, Barbara Frittoli, Vivica Genaux, Massimo Giordano, Andrew Kennedy, Alessandra Marianelli, Peter Mattei, Sally Matthews, Francesco Meli, Maxim Mironov, Tomislav Muzek, Laura Polverelli, Nicola Ulivieri, Franco Vassallo.

Question: Siegfried and Idomeneo are both what type of performances?
Answer: music