Question: Der Messias, K. 572, is Wolfgang Amadeus Mozart's 1789 German-language version of the 1741 oratorio, "Messiah", by which German, later British, baroque composer who spent the bulk of his career in London, becoming well known for his operas, oratorios, anthems, and organ concertos, and received important training in Halle and worked as a composer in Hamburg and Italy before settling in London?
Context: Susannah Maria Cibber (February 1714 – 30 January 1766), also known as Susannah Maria Arne, was a celebrated English singer and actress and the sister of the composer Thomas Arne.  Although she began her career as a soprano, her voice lowered in the early part of her career to that of a true contralto.  She was universally admired for her ability to move her audiences emotionally both as an actress and vocalist.  Possessing a sweet, expressive, and agile singing voice with a wide vocal range, Cibber was an immensely popular singer, even if at times her voice was criticized for a lack of polished technique.  Charles Burney wrote of her singing that "by a natural pathos, and perfect conception of the words, she often penetrated the heart, when others, with infinitely greater voice and skill, could only reach the ear."  Cibber was particularly admired by Handel, who wrote numerous parts especially for her including the contralto arias in his 1741 oratorio "Messiah", the role of Micah in "Samson", the role of Lichas in "Hercules" and the role of David in "Saul" among others.  In the mid-1730s she began appearing in plays in addition to appearing in operas and oratorios.  She became the greatest dramatic actress of the eighteenth century London stage and at the time of her death was the highest paid actress in England. Franz Xaver Wolfgang Mozart (26 July 1791 – 29 July 1844), also known as Wolfgang Amadeus Mozart, Jr., was the youngest child of six born to Wolfgang Amadeus Mozart and his wife Constanze.  He was the younger of his parents' two surviving children.  He was a composer, pianist, conductor, and teacher from the late classical period whose musical style was of an early Romanticism, heavily influenced by his father's mature style. The Handel organ concertos Op 7, HWV 306–311, refer to the six organ concertos for organ and orchestra composed by George Frideric Handel in London between 1740 and 1751, published posthumously in 1761 by the printing company of John Walsh.  They were written for performance during Handel's oratorios, contain almost entirely original material, including some of his most popular and inspired movements. The Piano Concerto No. 25 in C major, K.  503, was completed by Wolfgang Amadeus Mozart on December 4, 1786, alongside the Prague Symphony, K. 504.  Although two more concertos (K. 537 and K. 595) would later follow, this work is the last of what are considered the twelve great piano concertos written in Vienna between 1784 and 1786.  Chronologically the work is the 21st of Mozart's 23 original piano concertos. Félix Rienth (born 24 June 1970) is a Swiss operatic tenor.  Born in Basel, he was a member of the Basel Boys Choir in his youth.  He made his first opera appearance as a boy with Theater Basel as the first boy in Wolfgang Amadeus Mozart's "The Magic Flute".  He attended the University of Basel where he earned diplomas in the Spanish and German languages.  He then studied singing privately in Basel with Heidi Wölnerhanssen before entering the Hochschule der Künste Bern; graduating from there in 2000 with a degree in opera performance.  He has since had a major career as a concert singer in the oratorio repertoire; appearing with important ensembles and at major music festivals throughout Europe, including a recital in presence of Her Majesty, Queen Fabiola of Belgium.  He has made about 20 recordings on a variety of labels.  A highly acclaimed production was the recording of Johann Christoph Pepusch]]'s "Tenor Cantatas" with his wife, Muriel Rochat Rienth, recorder player, and Swiss baroque ensemble "La Tempesta Basel".  His CD of Spanish baroque songs "Tonos humanos" by José Marín was considered as a reference recording by German magazine "Klassik heute".  2014 is appearing Georg Philipp Telemann's "Tenor Cantatas" with "La Tempesta Basel", elected among "Best CDs of the month" by Spanish magazine RITMO. Der Messias, K. 572, is Wolfgang Amadeus Mozart's 1789 German-language version of "Messiah", George Frideric Handel's 1741 oratorio.  On an initiative of Gottfried van Swieten, Mozart adapted Handel's work for performances in Vienna. The Handel organ concertos Op 4, HWV 289–294, refer to the six organ concertos for chamber organ and orchestra composed by George Frideric Handel in London between 1735 and 1736 and published in 1738 by the printing company of John Walsh.  Written as interludes in performances of oratorios in Covent Garden, they were the first works of their kind for this combination of instruments and served as a model for later composers. George Frideric (or Frederick) Handel ( ; born Georg Friedrich Händel ] ; 23 February 1685 (O.S.) [(N.S.) 5 March] – 14 April 1759) was a German, later British, baroque composer who spent the bulk of his career in London, becoming well known for his operas, oratorios, anthems, and organ concertos. Handel received important training in Halle and worked as a composer in Hamburg and Italy before settling in London in 1712; he became a naturalised British subject in 1727.  He was strongly influenced both by the great composers of the Italian Baroque and by the middle-German polyphonic choral tradition. George Frideric Handel (23 February 1685 – 14 April 1759) was a German–English Baroque composer who is famous for his operas, oratorios and concerti grossi.  Handel's compositions include 42 operas; 29 oratorios; more than 120 cantatas, trios and duets; numerous arias; chamber music; a large number of ecumenical pieces; odes and serenatas; and 16 organ concerti.  His oratorio "Messiah", with its "Hallelujah" chorus, is among the most famous Baroque works and is a popular choice for performances during the Christmas season.  Among Handel's best-known instrumental works are the Concerti Grossi Opus 3 and 6; "The Cuckoo and the Nightingale", in which birds are heard calling during passages played in different keys representing the vocal ranges of two birds; and his 16 keyboard suites, especially "The Harmonious Blacksmith". Amadeus is a 1984 American period drama film directed by Miloš Forman, adapted by Peter Shaffer from his stage play "Amadeus".  The story, set in Vienna, Austria, during the latter half of the 18th century, is a fictionalized biography of Wolfgang Amadeus Mozart.  Mozart's music is heard extensively in the soundtrack of the movie.  The film follows Italian composer Antonio Salieri at the court of Emperor Joseph II, and his jealous vendetta against his younger rival, Wolfgang Amadeus Mozart.
Answer: George Frideric Handel