Question: What German composer wrote a letter in 1770 addressing Lucrezia Aguiari's ability to perform in C sporano acuto?

full_context: Document 1: Soprano: A soprano ] is a type of classical female singing voice and has the highest vocal range of all voice types. The soprano's vocal range (using scientific pitch notation) is from approximately middle C (C) = 261 Hz to "high A" (A) =880 Hz in choral music, or to "soprano C" (C, two octaves above middle C) =1046 Hz or higher in operatic music. In four-part chorale style harmony, the soprano takes the highest part, which usually encompasses the melody.
Document 2: Mozart family grand tour: The Mozart family grand tour was a journey through western Europe, undertaken by Leopold Mozart, his wife Anna Maria, and their musically gifted children Maria Anna (Nannerl) and Wolfgang Amadeus from 1763 to 1766. At the start of the tour the children were aged eleven and seven respectively. Their extraordinary skills had been demonstrated during a visit to Vienna in 1762, when they had played before the Empress Maria Theresa at the Imperial Court. Sensing the social and pecuniary opportunities that might accrue from a prolonged trip embracing the capitals and main cultural centres of Europe, Leopold obtained an extended leave of absence from his post as deputy Kapellmeister to the Prince-Archbishop of Salzburg. Throughout the subsequent tour, the children's "Wunderkind" status was confirmed as their precocious performances consistently amazed and gratified their audiences.
Document 3: Lucrezia Aguiari: Lucrezia Aguiari (sometimes spelled Agujari) (Ferrara 1743/1746 – Parma 18 May 1783) was an Italian coloratura soprano. She possessed an unusually agile voice with a large vocal range that spanned slightly more than three and a half octaves; faculties that enabled her to perform the most difficult passage work. In a letter dated 24 March 1770 Leopold Mozart wrote of hearing her perform a C an octave above high C at the Ducal opera of Parma, "I could not believe that she was able to reach C soprano acuto, but my ears convinced me." Aldous Huxley also mentioned this event in his novel, "Brave New World", (misspelt as 'Ajugari').
Document 4: O, wie will ich triumphieren: "O, wie will ich triumphieren" (or, "Ha, wie will ich triumphieren"), is an aria for low bass from Mozart's "singspiel" "Die Entführung aus dem Serail". It is well known for the extraordinary technical demands it makes on the singer, and is sometimes performed in recitals and featured in anthologies by basses who are able to sing it. It features rapid precision-coloratura, abrupt octave-leaps between the upper and lower registers, and extended low notes, including a drawn-out low D (D, one of the lowest notes demanded of any voice in opera). Mozart wrote it with one particular bass in mind: the very famous Ludwig Fischer.
Document 5: Wolfgang Amadeus Mozart: Wolfgang Amadeus Mozart ( ; ; ] ; 27 January 1756 – 5 December 1791), baptised as Johannes Chrysostomus Wolfgangus Theophilus Mozart, was a prolific and influential composer of the Classical era.
Document 6: 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 7: Versuch einer gründlichen Violinschule: Versuch einer gründlichen Violinschule ("A Treatise on the Fundamental Principles of Violin Playing") is a textbook for instruction in the violin, published by Leopold Mozart in 1756. The work was influential in its day, and continues to serve as a scholarly source concerning 18th century performance practice.
Document 8: Pietro Antonio Lorenzoni: Pietro Antonio Lorenzoni (1721–1782) was an Italian painter who is believed to have painted several portraits of Wolfgang Amadeus Mozart and his family: "The Boy Mozart" (1763), his sister Maria Anna Mozart in "Nannerl as a Child" (1763) and a portrait of their father Leopold Mozart (c. 1765). He arrived in Salzburg, Austria in the 1740s and first wanted to paint Wolfgang and Nannerl. His protégé, Johann Nepomuk della Croce, painted a Mozart family portrait in 1780.
Document 9: Leopold Mozart: Johann Georg Leopold Mozart (November 14, 1719 – May 28, 1787) was a German composer, conductor, teacher, and violinist. Mozart is best known today as the father and teacher of Wolfgang Amadeus Mozart, and for his violin textbook "Versuch einer gründlichen Violinschule".
Document 10: Nannerl Notenbuch: The Nannerl Notenbuch , or Notenbuch für Nannerl (English: Nannerl's Music Book) is a book in which Leopold Mozart, from 1759 to about 1764, wrote pieces for his daughter, Maria Anna Mozart (known as "Nannerl"), to learn and play. His son Wolfgang also used the book, in which his earliest compositions were recorded (some penned by his father). The book contains simple short keyboard (typically harpsichord) pieces, suitable for beginners; there are many anonymous minuets, some works by Leopold, and a few other composers including Carl Philipp Emanuel Bach and the Austrian composer Georg Christoph Wagenseil. There are also some technical exercises, a table of intervals, and some modulating figured basses. The notebook originally contained 48 bound pages of music paper, but only 36 pages remain, with some of the missing 12 pages identified in other collections.
Document 11: Josef Mysliveček: Josef Mysliveček (9 March 1737 – 4 February 1781) was a Czech composer who contributed to the formation of late eighteenth-century classicism in music. Mysliveček provided his younger friend Wolfgang Amadeus Mozart with significant compositional models in the genres of symphony, Italian serious opera, and violin concerto; both Wolfgang and his father Leopold Mozart considered him an intimate friend from the time of their first meetings in Bologna in 1770 until he betrayed their trust over the promise of an operatic commission for Wolfgang to be arranged with the management of the Teatro San Carlo in Naples. He was close to the Mozart family, and there are frequent references to him in the Mozart correspondence.
Document 12: Ludmilla Azova: Ludmilla Azova is a soprano opera singer who studied at the New York College of Music and has appeared as a soloist with the New York Philharmonic and the National Orchestra Association, and also performed the role of Fiordiligi in Mozart's "Così fan tutte" with the Bermuda Festival Theatre. Other operatic roles performed in New York include Mimi in "La bohème", "Madame Butterfly" and Marguerite in "Faust". In 1966, she appeared as Anna Gomez in a production of Gian Carlo Menotti's "The Consul" at New York City Opera. Azova has also been an active recitalist.In a review, dated October 6, 1969, in the New York Times, Peter G. Davis wrote, "Ludmilla Azova brought a bright, silvery soprano and an abundance of authoritative style to her Russian song recital at Town Hall late yesterday afternoon.Born in Europe of Russian parents, Miss Azova clearly knows where of what she sings...In addition to the charm and elegance of her interpretations, Miss Azova's well-schooled, even, secure soprano consistently delighted the ear... She is a beautiful woman, a charming recitalist and a singer of accomplishment."
Document 13: Cecilia Bartoli: Cecilia Bartoli, (] ; born 4 June 1966) is an Italian coloratura mezzo-soprano opera singer and recitalist. She is best known for her interpretations of the music of Mozart and Rossini, as well as for her performances of lesser-known Baroque and classical music. She is known for having the versatility to sing soprano and mezzo roles.
Document 14: Lyric soprano: A lyric soprano is a type of operatic soprano voice that has a warm quality with a bright, full timbre that can be heard over an orchestra. The lyric soprano voice generally has a higher tessitura than a soubrette and usually plays ingenues and other sympathetic characters in opera. Lyric sopranos have a range from approximately middle C (C4) to "high D" (D6). This is the most common female singing voice. There is a tendency to divide lyric sopranos into two groups, light and full.
Document 15: Georgia Brown (Brazilian singer): Georgia Brown, pseudonym of Rossana Monti (born June 29, 1980) is an Italian Brazilian singer noted for her extensive vocal range. She was listed in the 2005 "Guinness World Records" for hitting the highest vocal note and for possessing the greatest vocal range for a female, claimed to be exactly eight octaves from G-G using scientific pitch notation. However, as of 2013, Tim Storms holds the record for the widest vocal range of any human with 10 octaves.
ground_truth: Leopold Mozart