sentences:  piano, violin and violoncello, and from the clarinet-violin-piano trio and the clarinet-cello-piano trio by the fact that the viola and the clarinet share roughly the same range.The combination of viola and clarinet is thus distinguished by the timbre (tone quality or colour) of the instruments rather than register (high versus low ranges, like violin compared with cello).Austrian composer Wolfgang Amadeus Mozart (1756–1791) was the first to write for this combination of instruments with his "Kegelstatt" Trio, K. 498 (1786).