What is the longest symphony?
Symphony No. 3 (Mahler)
The Symphony No. 3 by Gustav Mahler was written in 1896, or possibly only completed in that year, but composed between 1893 and 1896. It is his longest piece and is the longest symphony in the standard repertoire, with a typical performance lasting around 90 to 105 minutes. It was voted one of the ten greatest symphonies of all time in a survey of conductors carried out by the "BBC Music Magazine".
Symphony No. 5 (Beethoven)
The Symphony No. 5 in C minor of Ludwig van Beethoven, Op. 67, was written between 1804 and 1808. It is one of the best-known compositions in classical music, and one of the most frequently played symphonies. First performed in Vienna's Theater an der Wien in 1808, the work achieved its prodigious reputation soon afterward. E. T. A. Hoffmann described the symphony as "one of the most important works of the time". As is typical of symphonies in the classical period, Beethoven's Fifth Symphony is in four movements.