Louis Spohr (1784-1859), a German composer, conductor, and violinist, formed an acquaintance with Beethoven and, although greatly critical of his ninth symphony, promoted much of his work.  His innovations include the violin chinrest and the rehearsal mark.  From 1822 until the end of his life, at the prompting of Carl Maria von Weber, he served under William II at the court of Kassel.  Despite its gloomy opening, the CONCERTANTE QUARTET (STRING QUARTET CONCERTO) in A minor, Op. 131, is a warm and richly melodic work scored for string quartet and orchestra. Instrumentation: 2.2.2.2: 2.2.3.0: Timp: Str (4.4.3.3.3: Solo Str Quartet in set).