The term string quartet refers to either a type of musical composition or a group of four people who play them. Many composers from the mid-18th century onwards wrote string quartets. The associated musical ensemble consists of two violinists, a violist, and a cellist. The double bass is almost never used in the ensemble mainly because it would sound too loud and heavy.
The Fitzwilliam Quartet
A string quartet in performance. From left to right: violin 1, violin 2, viola, cello
Joseph Haydn playing in a string quartet
End of Arensky's String Quartet No. 2 for violin, viola and two cellos, played at the Casals Forum in 2023
The Classical Period was an era of classical music between roughly 1750 and 1820.
A modern string quartet. In the 2000s, string quartets from the Classical era are the core of the chamber music literature. From left to right: violin 1, violin 2, cello, viola
Gluck, detail of a portrait by Joseph Duplessis, dated 1775 (Kunsthistorisches Museum, Vienna)
Haydn portrait by Thomas Hardy, 1792