Beethoven developed the string quartet to the point where many consider it reached its peak of perfection, offering, as always, a challenge to later composers. His Quartet in B flat, Opus 130, includes the heartfelt Cavatina, a slow movement much admired and treasured too by the composer himself, a contrast to the lighter hearted German dance that precedes it. The original last movement, the masterly Great Fugue, proved immensely demanding and Beethoven was persuaded to allow it to be published as a separate work.