String Quintet No. 3 (Mozart)

The String Quintet No. 3 in C major, K. 515 was written by Wolfgang Amadeus Mozart. Like all of Mozart’s string quintets, it is a “viola quintet” in that it is scored for string quartet and an extra viola (two violins, two violas and cello).

The work was completed on April 19, 1787, less than a month before the completion of his stormy G Minor Quintet, K. 516. This would not be the last time that a great pair of C major/G minor works of the same form would be published in close proximity and assigned consecutive Köchel numbers. The following year, the 40th (G minor) and 41st (C major) symphonies would be completed within a few weeks of each other.

https://en.wikipedia.org/wiki/String_Quintet_No._3_(Mozart)

Joseph Haydn

Portrait of Joseph Haydn by Thomas Hardy (1791)[1]

(Franz) Joseph Haydn[a] (/ˈhdən/German: [ˈfʁants ˈjoːzɛf ˈhaɪdn̩] (About this sound listen); 31 March[b] 1732 – 31 May 1809) was an Austrian composer of the Classical period. He was instrumental in the development of chamber music such as the piano trio.[2] His contributions to musical form have earned him the epithets “Father of the Symphony” and “Father of the String Quartet“.[3]

Haydn spent much of his career as a court musician for the wealthy Esterházy family at their remote estate. Until the later part of his life, this isolated him from other composers and trends in music so that he was, as he put it, “forced to become original”.[c] Yet his music circulated widely, and for much of his career he was the most celebrated composer in Europe.

He was a friend and mentor of Mozart, a tutor of Beethoven, and the older brother of composer Michael Haydn.

https://en.wikipedia.org/wiki/Joseph_Haydn