Question: Who was the main subject of biographies of the composer of Piece in F for Keyboard, K. 33b?

full_context: Document 1: Kyrie in F major, K. 33: The piece shows the influence of Johann Schobert and French church music. It is based upon a French song. The piece is about nine minutes long. The manuscript shows that Mozart's father edited the piece. In the piece, the alto voice is supported by the first violin, the soprano by the second, the viola reinforces the tenor and occasionally the alto. At times, the first violin unites with the canto, in order that the leading highest part may stand out more clearly. The support of the alto voice by the highest stringed instrument, mostly in the higher octave, makes the alto stand out clearly in the harmony against the soprano.
Document 2: 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 3: Classical period (music): However, Vienna's fall as the most important musical center for orchestral composition during the late 1820s, precipitated by the deaths of Beethoven and Schubert, marked the Classical style's final eclipse -- and the end of its continuous organic development of one composer learning in close proximity to others. Franz Liszt and Frédéric Chopin visited Vienna when they were young, but they then moved on to other cities. Composers such as Carl Czerny, while deeply influenced by Beethoven, also searched for new ideas and new forms to contain the larger world of musical expression and performance in which they lived.
Document 4: 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 5: 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 6: 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 7: Piece in F for Keyboard, K. 33B (Mozart): Mozart wrote this piece in pencil on the back of a circular by the Zürcher Musikkollegium (Zürich Music College) dated 30 September 1766, when the Mozart family came to the end of their Grand Tour. The circular invited sponsors, music lovers and other people who might be interested to concerts by "the young (9 years old) Master Mozart as well as his maiden sister" (Maria Anna – Nannerl) on October 7 and 9. It can be assumed that Mozart played or improvised this lively piece in one of those concerts, the programs to which are lost. Mozart wrote it on the back of the circular probably as a souvenir for the College's board; otherwise he would have used his sister's notebook or his third book of sketches (""), which is also lost. The autograph became known very late (in 1942), and so is missing from Alfred Einstein's 3rd edition of the Köchel catalogue.
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: Concerto for Violin, Piano, and Orchestra (Mozart): Mozart only wrote the first 120 bars of the first movement, and only the first 74 bars are completely scored. Alfred Einstein believed that the work was abandoned due to the disbanding of the Mannheim orchestra; however, that had happened earlier that year when the Elector moved to Munich and most of his orchestra followed him, so the "Academie des Amateurs" replaced the Mannheim orchestra. The most likely explanation for the concerto being abandoned is that Mozart left Mannheim in December 1778, perhaps because the "Academie" did not start as early as he thought it would. It is unknown why he did not continue working on the concerto on his journey home or when he was back in Salzburg.
Document 10: 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 11: Classical period (music): The best - known composers from this period are Joseph Haydn, Wolfgang Amadeus Mozart, Ludwig van Beethoven, and Franz Schubert; other notable names include Luigi Boccherini, Muzio Clementi, Antonio Salieri, Leopold Mozart, Johann Christian Bach, Carl Philipp Emanuel Bach, and Christoph Willibald Gluck. Ludwig van Beethoven is regarded either as a Romantic composer or a Classical period composer who was part of the transition to the Romantic era. Franz Schubert is also a transitional figure, as were Johann Nepomuk Hummel, Luigi Cherubini, Gaspare Spontini, Gioachino Rossini, and Carl Maria von Weber. The period is sometimes referred to as the era of Viennese Classic or Classicism (German: Wiener Klassik), since Gluck, Mozart, Haydn, Salieri, Schubert, and Beethoven all worked in Vienna.
Document 12: 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.
Document 13: 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 14: London Sketchbook (Mozart): Most pieces are extremely short, normally lasting from 40 seconds to a minute; however, some span as long as four minutes in total (see K. 15t). According to the "Neue Mozart-Ausgabe", the intended purpose of this book was not for musical exercise, as once thought, rather for the young Mozart, who had just learned how to use pen and ink, to write down his own inspiration without needing anyone's help. Corrections by his father Leopold appear in pencil only.
Document 15: Piano Concertos Nos. 1–4 (Mozart): Wolfgang Amadeus Mozart began his series of preserved piano concertos with four that he wrote at the age of 11, in Salzburg: K. 37 and 39–41. The autographs, all held by the Jagiellonian Library, Kraków, are dated by his father as having been completed in April (K. 37) and July (K. 39–41) of 1767. Although these works were long considered to be original, they are now known to be orchestrations of sonatas by various German virtuosi. The works on which the concertos are based were largely published in Paris, and presumably Mozart and his family became acquainted with them or their composers during their visit to Paris in 1763–64.
ground_truth: Wolfgang Amadeus Mozart
sub_queries: Piece in F for Keyboard, K. 33b >> composer Answer: Mozart
Biographies of Mozart >> main subject Answer: Wolfgang Amadeus Mozart