Short answers, pulled from the story.
Schubert composed more than 1,500 works in his short career. These include over 600 Lieder for solo voice and piano, seven complete symphonies, sacred music, operas, chamber music, and a large body of piano works.
Schubert died on the 19th of November 1828, aged 31, and the official cause was typhoid fever. Some historians have proposed syphilis, which Schubert first showed symptoms of in 1823, though the researcher Eva M. Cybulska has argued that syphilis is a conjecture and that the diagnosis traces back to the biographer Otto Deutsch in 1907.
Among his best-known compositions are the songs "Gretchen am Spinnrade" and "Erlkönig," the song cycles Die schöne Müllerin and Winterreise, the Symphony No. 8 in B minor (the Unfinished), the Symphony No. 9 in C major (the Great), the Trout Quintet, and the String Quartet No. 14 in D minor (Death and the Maiden).
Schubert was born on the 31st of January 1797 in the Himmelpfortgrund suburb of Vienna, now part of the Alsergrund district. He was the twelfth child of schoolmaster Franz Theodor Schubert and his wife Maria Elisabeth Katharina Vietz.
The reason Schubert left the Symphony No. 8 in B minor unfinished - after writing two movements and sketches into a third - has never been definitively established and continues to be discussed by scholars. Notably, as the musicologist Brian Newbould observed, Schubert never mentioned the work to any of his friends despite appearing to be thrilled by what he was achieving.
Appreciation of Schubert's music while he was alive was limited to a relatively small circle of admirers in Vienna. He gave only one public concert of his own works, on the 26th of March 1828, nine months before his death. Wider recognition came largely after his death, when composers including Felix Mendelssohn, Robert Schumann, and Franz Liszt discovered and championed his music.