Beethoven's String Quartet No. 16 in F major (Opus 135) was written in 1826 and was the last substantial work he finished (only the replacement last movement of the Quartet Op. 130 was written later). It is on a smaller scale and less revolutionary than his other late quartets. Under the introductory slow chords in the last movement Beethoven wrote in the manuscript "Muss es sein?" (Must it be?) to which he responds, with the faster main theme theme of the movement, "Es muss sein!" (It must be!)

1. Allegretto
2. Vivace
3. Lento assai, cantante e tranquillo
4. Grave ma troppo tratto - Allegro

See also : Beethoven, List of works by Beethoven