Budapest String Quartet was a string ensemble established in 1917 in Kolozsvár, Hungary. The group originally consisted of first violinist Emil Hauser, second violinist Alfred Indig, violist István Ipolyi, and cellist Harry Son. They performed their debut concert in December 1917 and relocated to Berlin in the early 1920s due to political unrest. In 1925, the ensemble debuted in London and signed a recording contract with the label His Master's Voice. They underwent several lineup changes, including the addition of Josef Roisman in 1927 and cellist Mischa Schneider in 1930. Between 1940 and 1967, the ensemble made recordings for the label Columbia Records. Their discography included the studio recording Beethoven String Quartets Op. 59 No. 3 & Op. 74 (1991) and the compilation recording The Complete String Quartets (2010). The group reached wider visibility when their recording of the “Cavatina” from the String Quartet No. 13 in B flat major, Op. 130 by the composer Ludwig van Beethoven was included on the NASA Voyager Golden Record in 1977. The musician Jascha Heifetz described the ensemble as a revolution of four Russians. The quartet became inactive in 1967.