The string quartet dates from at least the 1750s, with the works of Franz Xaver Richter, Luigi Boccherini, and early Haydn.
It's actually fairly hard to pin down, though. Two violins, viola, and cello is also the standard string section of an orchestra, so how do we know something was written for just four players and not for an ensemble of varying numbers?
By the time we get to Haydn's mature quartets it is obvious--it would sound silly for a string orchestra to play these soloistic parts. But in his op. 1, there isn't that distinction. In fact, there are optional wind parts for some of the op. 1 quartets, which leads us to think they may also have been performed as divertimentos or even as small symphonies.
The Guarneri Quartet was an American string quartet founded in 1964 and disbanded in 2009.
nuno flores string quartet or corvonuno string quartet
Concord String Quartet was created in 1971.
Emerson String Quartet was created in 1976.
Australian String Quartet was created in 1985.
Oberlin String Quartet ended in 1959.
Oberlin String Quartet was created in 1955.
Hollywood String Quartet was created in 1939.
Orion String Quartet was created in 1987.
Atrium String Quartet was created in 2000.
Cypress String Quartet was created in 1996.
Tokyo String Quartet was created in 1969.