- David Fenton
A composition for piano and four other instruments, usually, after 1800, string quartet. Along with the Piano quartet, the form was one of a handful of standardized instrumentations that grew out of the accompanied keyboard sonatas or divertimentos during the second half of the 18th century (see Accompanied keyboard music) and is loosely related to the keyboard concerto. Some early concertos (such as the three of Mozart's dating from 1782–3) can be performed ‘a quattro’, which is usually taken to mean by piano and string quartet, but have important formal differences from quintets proper; some quintets however show concerto-derived characteristics. The standard scoring emerged later than for the piano quartet, but some time after the rise of the string quartet in the 1770s and 80s, and it was not until the second quarter of the 19th century that the scoring with string quartet came to eclipse all others....