Question: Who is the main subject of biographies of the composer of Horn Concerto No. 1?

full_context: Document 1: Franz Xaver Wolfgang Mozart: 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.
Document 2: Horn Concerto No. 3 (Mozart): Wolfgang Amadeus Mozart's Horn Concerto No. 3 in E-flat major, K. 447, was completed between 1784 and 1787, during the Vienna Period.
Document 3: Mozart's birthplace: Mozart's birthplace (German: ' or ') was the birthplace of Wolfgang Amadeus Mozart at No. 9 Getreidegasse in Salzburg, Austria. The Mozart family resided on the third floor from 1747 to 1773. Mozart himself was born here on 27 January 1756. He was the seventh child of Leopold Mozart, who was a musician of the Salzburg Royal Chamber.
Document 4: Wolfgang Amadeus Mozart: Wolfgang Amadeus Mozart was born on 27January 1756 to Leopold Mozart (1719–1787) and Anna Maria, née Pertl (1720–1778), at 9 Getreidegasse in Salzburg. This was the capital of the Archbishopric of Salzburg, an ecclesiastic principality in what is now Austria, then part of the Holy Roman Empire. He was the youngest of seven children, five of whom died in infancy. His elder sister was Maria Anna Mozart (1751–1829), nicknamed "Nannerl". Mozart was baptised the day after his birth, at St. Rupert's Cathedral in Salzburg. The baptismal record gives his name in Latinized form, as "Joannes Chrysostomus Wolfgangus Theophilus Mozart". He generally called himself "Wolfgang Amadè Mozart" as an adult, but his name had many variants.
Document 5: Symphony, K. 45b (Mozart): This work was only known to Ludwig Ritter von Köchel as an incipit in the catalogue of Breitkopf & Härtel, and thus it was placed in the Anhang as K. Anh. 214. Alfred Einstein then discovered a set of parts in the Berlin State Library with the title ""Synfonia Ex Bb...Del Sigr. cavaliere Amadeo Wolfgango Mozart Maestro di concerto di S.A. á Salisburgo"". Wolfgang became the Concertmaster to the Archbishop of Salzburg in November 1769, and was given the title "cavaliere" in July 1770, but as this is a later copy, this information cannot be used for dating purposes. Einstein believed the symphony to date from early 1768 on stylistic grounds; Neal Zaslaw and Gerhard Allroggen believe even earlier dates to also be possible, and Zaslaw dated the symphony cautiously to Salzburg in 1767. Einstein also believed that the symphonies in the catalogue of Breitkopf & Härtel were sent by Leopold Mozart to be published.
Document 6: Violin Concerto No. 1 (Mozart): Wolfgang Amadeus Mozart's Violin Concerto No. 1 in B-flat major, K. 207, once was supposed to have been composed in 1775 (when Mozart was 19), along with the other four wholly authentic violin concertos. However, analysis of handwriting and the manuscript paper on which the concerto was written suggest that the date of composition might have been 1773. It has the usual fast-slow-fast structure.
Document 7: Sinfonia Concertante for Four Winds: The Sinfonia Concertante for Four Winds in E flat major is a work thought to be by Wolfgang Amadeus Mozart, for oboe, clarinet, horn, bassoon, and orchestra, K. 297b (Anh. C 14.01). He originally wrote a work for flute, oboe, horn, bassoon, and orchestra, K. Anh. 9 (297B), in Paris in April 1778. There is considerable debate about the relation of the work as it is performed today to this original work.
Document 8: Piano Concertos K. 107 (Mozart): These concertos remained unpublished in the Alte Mozart-Ausgabe, the first complete edition of Mozart's works, so they were not given a number by the publishers of that edition, Breitkopf & Härtel (as the other 27 concerti were given in that publication). Therefore, when these works are enumerated with the rest, it can be seen that Mozart composed 30 keyboard concerti. These three works, however, and the concerti numbered as Piano Concertos 1 through 4 are actually not original compositions, but arrangements of works by other composers.
Document 9: Horn Concerto No. 1 (Mozart): This is one of two horn concertos of Mozart to include bassoons (the other is K. 447), but in this one he "treats them indifferently in the first movement." It is the only one of Mozart's horn concertos to be in D major (the rest are in E-flat major) and the only one to have just two movements instead of the usual three (with the exception of the incompletely scored horn concerto, K. 370b+371).
Document 10: Wolfgang Amadeus Mozart: Wolfgang Amadeus Mozart (/ ˈwʊlfɡæŋ æməˈdeɪəs ˈmoʊtsɑːrt / MOHT - sart; German: (ˈvɔlfɡaŋ amaˈdeːʊs ˈmoːtsaʁt); 27 January 1756 -- 5 December 1791), baptised as Johannes Chrysostomus Wolfgangus Theophilus Mozart, was a prolific and influential composer of the Classical era.
Document 11: Horn Concertos (Mozart): The Horn Concertos by Wolfgang Amadeus Mozart were written for his friend Joseph Leutgeb whom he had known since childhood. Leutgeb was a skilled player, as the works are very difficult to perform on the natural horn of the period, requiring lip trills, much hand-stopping, and rapid tonguing.
Document 12: Biographies of Mozart: Wolfgang Amadeus Mozart died after a short illness on 5 December 1791, aged 35. His reputation as a composer, already strong during his lifetime, rose rapidly in the years after his death, and he became (as he has remained to this day) one of the most celebrated of all composers.
Document 13: Oboe Concerto (Mozart): Wolfgang Amadeus Mozart's Oboe Concerto in C major, K. 314 (271k), was composed in the spring or summer of 1777, for the oboist Giuseppe Ferlendis (1755–1802) from Bergamo. In 1778, Mozart re-worked it as a concerto for flute in D major. The concerto is a widely studied piece for both instruments and is one of the more important concertos in the oboe repertoire.
Document 14: Horn Sonata (Beethoven): Ludwig van Beethoven composed his Horn Sonata in F major, Op. 17 in 1800 for the virtuoso horn player Giovanni Punto. It was premiered with Punto as the soloist, accompanied on the piano by Beethoven himself in Vienna on April 18, 1800.
Document 15: Symphony No. 41 (Mozart): Wolfgang Amadeus Mozart completed his Symphony No. 41 in C major, K. 551, on 10 August 1788. The longest and last symphony that he composed, it is regarded by many critics as among the greatest symphonies in classical music.
ground_truth: Wolfgang Amadeus Mozart
sub_queries: Horn Concerto No. 1 >> composer Answer: Mozart
Biographies of Mozart >> main subject Answer: Wolfgang Amadeus Mozart