Walter Rabl (1873-1940) was a gifted composer who studied with J.F. Hummel and Karl Nawrátil. In 1896, his Quartet in E flat for Piano, Clarinet, Violin, and Cello, Op. 1 won 1st prize in a competition sponsored by the Vienna Tonkünstlerverein, of which Johannes Brahms was president. Brahms passed on the piece to his publisher, Simrock. This was a novel combination of instruments, possibly even the first piece written as such, and so Simrock published it in 1897 with an optional viola part to be used in place of the clarinet.