Group of 4 players (almost always 2 vn., va., vc.) or comp. written for them to play. Like the sym. in orch. mus., the str. qt. in chamber mus. has become the highest medium for a composer's thought. Form first developed at beginning of 18th cent. with A. Scarlatti, Tartini, etc., but achieved its flowering with Haydn, Mozart, Beethoven, and Schubert. Since then most composers have written str. qts., and the 19th and 20th cent. produced many superb qts. of performers, e.g. the Joachim, Brodsky, Bohemian, Léner, Griller, Amadeus, Gabrieli, Vermeer, Vegh, Chilingirian, Beethoven, Borodin, Endellion, Alban Berg, Takács, Kronos, Emerson, Arditti, Belcea, Sorrel, and the new Brodsky.