Brahms was retired in the 1890s when he went to hear Richard Muhlfeld perform a Clarinet concerto by Carl Maria V. Weber (likely his first, op.73). He was deeply impressed and came out of retirement to compose additional chamber music that included the B♭ (B-flat) Clarinet. Two sonatas for the clarinet emerged in the opus 120 catalogue in 1885, just two years before Brahms' death. These were instant hits when Brahms and Muhlfeld performed them. They were so loved that Johannes arranged them for the viola. Here you will find the viola version of Brahms' clarinet sonata no.1. Versions exist for the violin as well, but are fairly rarely played.