Question: What is the main subject of biographies of the composer of Piano Concerto No. 7?

full_context: Document 1: 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 2: 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 3: 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.
Document 4: 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 5: 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 6: 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 7: Piano Sonata No. 7 (Mozart): The work was composed during a journey to Mannheim and Paris in 1777-78. The sonata was completed in a few days in early November 1777. The andante movement is a "portrait" of his pupil Rose Cannabich, the 13-year-old daughter of the Mannheim Kapellmeister Christian Cannabich. Upon reviewing a copy of the manuscript, Mozart's father Leopold wrote that it was "a strange composition. It has something in it of the 'rather artificial' Mannheim style, but so very little that your own good style is not spoilt".
Document 8: Piano Sonata No. 17 (Mozart): Wolfgang Amadeus Mozart's Piano Sonata No. 17 in B major, K. 570, dated February 1789, is a sonata in three movements:
Document 9: 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 10: 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 11: 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 12: Piano Sonata No. 1 (Mozart): Wolfgang Amadeus Mozart's Piano Sonata No. 1 in C major, K. 279 / 189d (1774), is a piano sonata in three movements. It was written down, except for the first part of the opening movement, during the visit Mozart paid to Munich for the production of "La finta giardiniera" from late 1774 to the beginning of the following March. A typical performance of the sonata takes about 14 minutes. It is the first of his 18 piano sonatas. All but two of the sonatas, No. 8 in A minor and No. 14 in C minor, are in a major key. Also, the first six sonatas seem to follow the cycle of fifths, to the flat side first (No. 1 in C major, No. 2 in F major, No. 3 in B-flat major, No. 4 in E-flat major) and then to the sharp side (No. 5 in G major, No. 6 in D major).
Document 13: 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 14: Symphony No. 5 (Beethoven): While such resemblances sometimes occur by accident, this is unlikely to be so in the present case. Nottebohm discovered the resemblance when he examined a sketchbook used by Beethoven in composing the Fifth Symphony: here, 29 bars of Mozart's finale appear, copied out by Beethoven.
Document 15: Piano Concerto No. 7 (Mozart): Girdlestone, in his "Mozart and his Piano Concertos", describes the concerto and compares one of the themes of its slow movement to similar themes that turn up in later concertos – especially No. 25, K. 503 – in more developed forms.
ground_truth: Wolfgang Amadeus Mozart
sub_queries: Piano Concerto No. 7 >> composer Answer: Mozart
Biographies of Mozart >> main subject Answer: Wolfgang Amadeus Mozart