Question: Marie Haupt had several roles in the presentation of which German composer's works at the 1876 Bayreuth Festival?
Context: The Bayreuth Festspielhaus or Bayreuth Festival Theatre (German: Bayreuther Festspielhaus , ] ) is an opera house north of Bayreuth, Germany, dedicated solely to the performance of stage works by the 19th-century German composer Richard Wagner.  It is the venue for the annual Bayreuth Festival, for which it was specifically conceived and built.  Its official name is Richard-Wagner-Festspielhaus . Josephine Schefsky (sometimes spelled Schefzky) (1843 – 11 November 1912) was a German opera singer who had an active career during the latter half of the 19th century.  Possessing a powerful voice with a wide vocal range, she tackled roles from both the soprano and mezzo-soprano repertoires.  She is best remembered today for portraying several roles in the first complete presentation of Richard Wagner's "The Ring Cycle" at the very first Bayreuth Festival in 1876. The Bayreuth canon consists of those operas by the German composer Richard Wagner (1813–1883) that have been performed at the Bayreuth Festival.  The festival, which is dedicated to the staging of these works, was founded by Wagner in 1876 in the Bavarian town of Bayreuth, and has continued under the directorship of his family since his death.  Although it was not originally held annually, it has taken place in July and August every year since the 75th anniversary season in 1951.  Its venue is the Bayreuth Festspielhaus, which was built for the first festival.  Attendance at the festival is often thought of as a pilgrimage made by Wagner aficionados. Luise Jaide (also Louise Jaide-Schlosser) (26 March 1842 – 2 January 1914) was a German operatic mezzo-soprano who had an active career during the latter half of the 19th century.  Among her signature roles were Amneris in "Aida", Azucena in "Il trovatore", Frau Reich in "The Merry Wives of Windsor", Idamante in "Idomeneo", Irmentraud in "Der Waffenschmied", and Mary in "The Flying Dutchman".  She is best remembered today for playing several roles in the first complete presentation of Richard Wagner's "The Ring Cycle" at the very first Bayreuth Festival in 1876. Marie Haupt (18 April 1849 – 1928) was a German operatic soprano who had an active career during the latter half of the 19th century.  She is best remembered today for portraying several roles in the first complete presentation of Richard Wagner's "The Ring Cycle" at the very first Bayreuth Festival in 1876. Bayreuth (] ; ) is a sizeable town in northern Bavaria, Germany, on the Red Main river in a valley between the Franconian Jura and the Fichtelgebirge Mountains.  The town's roots date back to 1194.  In the early 21st century, it is the capital of Upper Franconia and has a population of 72,148 (2015).  It is world-famous for its annual Bayreuth Festival, at which performances of operas by the 19th-century German composer Richard Wagner are presented. Cosima Wagner (born Francesca Gaetana Cosima Liszt; 24 December 1837 – 1 April 1930) was the illegitimate daughter of the Hungarian pianist and composer Franz Liszt and Marie d'Agoult.  She became the second wife of the German composer Richard Wagner, and with him founded the Bayreuth Festival as a showcase for his stage works; after his death she devoted the rest of her life to the promotion of his music and philosophy.  Commentators have recognised Cosima as the principal inspiration for Wagner's later works, particularly "Parsifal". Friederike Grün (14 June 1836- January 1917) was a German operatic soprano who had an active career during the latter half of the 19th century.  Possessing a powerful voice with a wide vocal range, she sang a broad repertoire that encompassed Italian, French, and German opera.  High points from her stage repertoire included the title heroine in Vincenzo Bellini's "Norma", Agathe in Carl Maria von Weber's "Der Freischütz", Leonore in "Fidelio", Rachel in Fromental Halévy's "La Juive", and Valentine in Giacomo Meyerbeer's "Les Huguenots".  She is best remembered today for portraying several roles in the first complete presentation of Richard Wagner's "The Ring Cycle" at the very first Bayreuth Festival in 1876. The Bayreuth Festival (German: Bayreuther Festspiele ) is a music festival held annually in Bayreuth, Germany, at which performances of operas by the 19th-century German composer Richard Wagner are presented.  Wagner himself conceived and promoted the idea of a special festival to showcase his own works, in particular his monumental cycle "Der Ring des Nibelungen " and "Parsifal". Wilhelm Richard Wagner ( ; ] ; 22 May 181313 February 1883) was a German composer, theatre director, polemicist, and conductor who is primarily known for his operas (or, as some of his later works were later known, "music dramas").  Unlike most opera composers, Wagner wrote both the libretto and the music for each of his stage works.  Initially establishing his reputation as a composer of works in the romantic vein of Weber and Meyerbeer, Wagner revolutionised opera through his concept of the "Gesamtkunstwerk" ("total work of art"), by which he sought to synthesise the poetic, visual, musical and dramatic arts, with music subsidiary to drama.  He described this vision in a series of essays published between 1849 and 1852.  Wagner realised these ideas most fully in the first half of the four-opera cycle "Der Ring des Nibelungen" ("The Ring of the Nibelung").
Answer: Wilhelm Richard Wagner