April Evans is an American soprano who has sung with the Opera Orchestra of New York where she sang Irene in Wagner's "Rienzi" in 1983 and with the Teater Kiel in Germany where she was the soprano soloist in Beethoven's "Missa solemnis" (1986) and 's "Thomas-Evangelium" (1987).
 She also appeared in a concert performance of Franchetti's rarely performed opera "Germania" with Bel Canto Opera (New York City, 1985).
Ludwig van Beethoven ( , ; ] ; baptised 17 December 177026 March 1827) was a German composer and pianist.
 A crucial figure in the transition between the Classical and Romantic eras in Western art music, he remains one of the most famous and influential of all composers.
 His best-known compositions include 9 symphonies, 5 piano concertos, 1 violin concerto, 32 piano sonatas, 16 string quartets, his great Mass the "Missa solemnis", and one opera, "Fidelio".
Sir Gilbert Levine, GCSG (born January 22, 1948) is an American conductor.
 He is considered an "outstanding personality in the world of international music television."
 He has led the PBS concert debuts of the Staatskapelle Dresden, Royal Philharmonic, London Philharmonic, Philharmonia Orchestra, WDR Symphony Orchestra, and the Pittsburgh Symphony, and the PBS premieres of works including the Beethoven Missa Solemnis, Bach Magnificat in D, Haydn Creation, and Bruckner Symphony 9.
The Sparrow Mass (German: Spatzenmesse ) is a mass in C major K. 220/196b, Mass No. 9, Missa brevis No. 5, composed by Wolfgang Amadeus Mozart in 1775 or 1776 in Salzburg.
 The mass is sometimes termed a missa brevis et solemnis , because it is short in a simple structure as a missa brevis, but festively scored like a missa solemnis with brass and timpani in addition to four soloists, strings and organ.
 It was possibly first performed on 7 April 1776 in a mass for Easter at the Salzburg Cathedral.
 The nickname is derived from violin figures in the Hosanna which resemble bird chirping.
The Cornell University Glee Club (CUGC) is the oldest student organization at Cornell University, having been organized shortly after the first students arrived on campus in 1868.
 The CUGC is a sixty-member chorus for male voices, with repertoire including classical, folk, 20th-century music, and traditional Cornell songs.
 The Glee Club also performs major works with the Cornell University Chorus such as Beethoven's Missa Solemnis, Handel's Messiah, and Bach's Mass in B Minor.
La Serenissima is a British early music/period instrument ensemble founded in 1994 by violinist Adrian Chandler, who has served as the group's director since its creation.
 Taking its name from "La Serenissima Repubblica di Venezia" (Italian for The Most Serene Republic of Venice), the ensemble specializes in the music of Venetian Baroque composer Antonio Vivaldi (1678–1741) and his contemporaries.
Nikolaus Harnoncourt (Johann Nikolaus Graf [Count] de la Fontaine und d’Harnoncourt-Unverzagt; 6 December 1929 – 5 March 2016) was an Austrian conductor, particularly known for his historically informed performances of music from the Classical era and earlier.
 Starting out as a classical cellist, he founded his own period instrument ensemble, Concentus Musicus Wien, in the 1950s, and became a pioneer of the Early Music movement.
 Around 1970, Harnoncourt started to conduct opera and concert performances, soon leading renowned international symphony orchestras, and appearing at leading concert halls, operatic venues and festivals.
 His repertoire then widened to include composers of the 19th and 20th centuries.
 In 2001 and 2003, he conducted the Vienna New Year's Concert.
 Harnoncourt was also the author of several books, mostly on subjects of performance history and musical aesthetics.
Elisabeth Kulman (born 28 June 1973) is an Austrian classical singer who has performed operatic roles in soprano, mezzo-soprano and contralto repertory.
 She has appeared at opera houses in Vienna and internationally.
 She has performed early operas such as Legrenzi's "Il Giustino" as well as new works, creating the role of Gora in the premiere of Reimann's "Medea" at the Vienna State Opera.
 She recorded Lieder by Mussorgsky, Bach's "Christmas Oratorio" with Peter Schreier and Beethoven's "Missa solemnis" with Nikolaus Harnoncourt.
 From 2015, she has focused on concert singing.
The Cornell University Chorus was founded in 1920, initially as the Cornell Women's Glee Club.
 The Chorus is a sixty-member treble choir, with repertoire including masses, motets, spirituals, classical, folk, 20th-century music, and traditional Cornell songs.
 Aside from its constantly changing and increasing selection of choral music for treble voices, the Chorus also performs major works with the Cornell University Glee Club such as Beethoven's Missa Solemnis, Handel's Messiah, Bach's Mass in B Minor and St Matthew Passion .
The Missa solemnis in D major, Op.
 123, is a solemn mass composed by Ludwig van Beethoven from 1819 to 1823.
 It was first performed on 7 April 1824 in St. Petersburg, Russia, under the auspices of Beethoven's patron Prince Nikolai Galitzin; an incomplete performance was given in Vienna on 7 May 1824, when the Kyrie, Credo, and Agnus Dei were conducted by the composer.
 It is generally considered one of the composer's supreme achievements and, along with Bach's Mass in B minor, one of the most significant Mass settings of the common practice period.

Question: What was the name of the period instrument ensemble that was formed in the 1950s by the conductor with whom Elisabeth Kulman recorded Beethoven's "Missa solemnis"?
Answer: Concentus Musicus Wien