Beethoven’s final string quartets are of such originality that throughout the nineteenth and early twentieth century they were considered to be exceptionally challenging. In these works Beethoven leaves far behind the commonly accepted compositional conventions of his time. Op.135 is the last substantial work Beethoven finished. It is smaller in scope and lighter in character than the other late quartets, yet its slow movement has great emotional penetration. Beethoven composed Op. 131 in 1826 and appears to have thought it his finest. Certainly nothing could surpass its depth, scope and originality.