Question: Which opera was performed first, The Midsummer Marriage or Hans Heiling?

Context articles: Dio, come ti amo
Hans Heiling (mythology)
Piano Concerto (Tippett)
Zauvijek volim te
Sweetwater (band)
Olive Gilbert
Amir Hosseinpour
The Midsummer Marriage
Hans Heiling
Michael Tippett

"Dio, come ti amo" (English translation: "God, How I Love You") was performed first time as duo by Domenico Modugno and Gigliola Cinquetti in San Remo Festival, 1966.
 Later it was the Italian entry in the Eurovision Song Contest 1966, performed in Italian by Domenico Modugno.
Hans Heiling (Jan Svatoš in Czech) is a legendary person in German and Bohemian mythology.
British composer Michael Tippett composed his Concerto for Piano and Orchestra between 1953 and 1955 on a commission from the City of Birmingham Symphony Orchestra.
 The overall character of the work was influenced by the composer's hearing German pianist Walter Gieseking rehearse Ludwig van Beethoven's Fourth Piano Concerto in 1950.
 Its musical content, while influenced by this concerto, was also shaped largely by Tippett's opera "The Midsummer Marriage", which he had completed in 1952.
 While Tippett had conceived the work initially in the mid-1940s, he had been preoccupied in much of the intervening time with "The Midsummer Marriage".
"Zauvijek volim te" (Cyrillic: Заувијек волим те, English translation: "I Love You Forever") is a song performed by Stefan Filipović, and was the Montenegrin entry for the Eurovision Song Contest 2008.
 It was performed first in the first semi-final on May 20, 2008 but failed to make it to the final.
 It got 23 points in total (12 from Bosnia and Herzegovina, 10 from Slovenia and 1 point from San Marino), which was enough only for a 14th place.The 10 and 12 points given make this song the best Montenegrin entry so far.
Sweetwater was an American rock band originally from Los Angeles, California.
 They were the act scheduled to open the Woodstock Festival in 1969; however, due to being stopped by the police on their way to the festival, folksinger Richie Havens' trio (Daniel Ben Zebulon, percussion, Paul "Deano" Williams, guitar, backing vocals) performed first.
 Sweetwater performed next, becoming the first band to perform at the festival.
Olive Sarah Gilbert (22 November 1898 – 19 February 1981) was a British singer and actress, who, in a career spanning seven decades, performed first in opera and then in many of Ivor Novello's musicals in London's West End.
Amir Hosseinpour is an opera director and choreographer who has worked in major opera houses around the world.
 He is a collaborator with directors such as Pierre Audi, founder of the Almeida Theatre, Nigel Lowery, and choreographer Jonathan Lunn.
 His production of Haydn's Orlando Paladino, co-directed with Nigel Lowery, continues to be broadcast on Sky Arts HD on a regular basis.
 Some of his biggest productions have been recorded for international DVD release.
 His choreography for Michael Tippett's The Midsummer Marriage at the Bavarian State Opera in February 1998 was described as 'stunning' by The Daily Telegraph critic, Rupert Christiansen, and it was also highly praised by Wolfgang Sandner in the Frankfurter Allgemeine Zeitung.
 Other outstanding reviews for Hosseinpour's work in the German-speaking newspaper Frankfurter Allgemeine Zeitung (FAZ) were for Les Paladins (Rameau) at Basel in December 2004, reviewed by Gerhard Koch, Petrushka at Munich reviewed by Jochen Schmidt in December 1999 and Orphée et Eurydice at the Bavarian State Opera in November 2003.
The Midsummer Marriage is an opera in three acts, with music and libretto by Michael Tippett.
 The work's first performance was at Covent Garden, 27 January 1955, conducted by John Pritchard.
 The reception of the opera was controversial, over perceived confusion as to the libretto and Tippett's use of symbols and psychological references.
 Nonetheless the opera has received at least ten more productions, including two further productions at the Royal Opera, in England, Wales, Scotland, Germany, Sweden and the United States.
Hans Heiling is a German Romantic opera in 3 acts with prologue by Heinrich Marschner with a libretto by Eduard Devrient, who also sang the title role at the première at the Königliche Hofoper (now Berlin State Opera), Berlin, on 24 May 1833, and went on to become Marschner's most successful opera.
 The opera brought the composer a considerable reputation, although this did not materially affect his position in Hanover, where he was music director of the Court Theatre.
 Like Marschner's other great success, "Der Vampyr", the plot of "Hans Heiling" makes great use of supernatural elements.
 As with several of his operas, "Hans Heiling" is based on a folk legend.
Sir Michael Kemp Tippett {'1': ", '2': ", '3': ", '4': "} (2 January 1905 – 8 January 1998) was an English composer who rose to prominence during and immediately after the Second World War.
 In his lifetime he was sometimes ranked with his contemporary Benjamin Britten as one of the leading British composers of the 20th century.
 Among his best-known works are the oratorio "A Child of Our Time", the orchestral "Fantasia Concertante on a Theme of Corelli", and the opera "The Midsummer Marriage".