A
string quartet is a musical ensemble of four string instruments usually two violins, a viola and cello or a piece written
to be performed by such a group.
The
string quartet is one of the most prominent chamber ensembles in classical music.
The form first came to be used after the middle of the 18th century.
Apparently , it was Joseph Haydn original "invention"...
Joseph Haydn''s first works were for string quartet.
It was very succesful in Europe and after that in the whole world.