 Mendelssohn 's mature output contains numerous chamber works , many of which display an emotional intensity lacking in some of his larger works . In particular , his String Quartet No. 6 , the last of his string quartets and his last major work – written following the death of his sister Fanny – is both powerful and eloquent . Other mature works include two other string quintets ; sonatas for the clarinet , cello , viola and violin ; and two piano trios . For the Piano Trio No. 1 in D minor , Mendelssohn uncharacteristically took the advice of his fellow composer , Ferdinand Hiller , and rewrote the piano part in a more romantic , " <unk> " style , considerably heightening its effect . 
