Webern's Opus 28 is in this genre, and he wrote Five Movements and Six Bagatelles in it. A work in this genre includes a "Holy song of thanksgiving" written after recovering from an illness, while another includes the epigram "Must it be?It must be! It must be!" Two earlier works in this genre use a "Thème Russe," and are part of a set of three from Beethoven's middle period. Beethoven's very last works, including a (*) Grosse Fuge, were in this genre. Beethoven wrote sixteen works in this genre, with nicknames like "Serioso," "Harp," and "Razumovsky." For 10 points, 
Webern's Opus 28 is in this genre, and he wrote Five Movements and Six Bagatelles in it. A work in this genre includes a "Holy song of thanksgiving" written after recovering from an illness, while another includes the epigram "Must it be?It must be! It must be!" Two earlier works in this genre use a "Thème Russe," and are part of a set of three from Beethoven's middle period. Beethoven's very last works, including a (*) Grosse Fuge, were in this genre. Beethoven wrote sixteen works in this genre, with nicknames like "Serioso," "Harp," and "Razumovsky." For 10 points, name this chamber ensemble composed of two violins, a viola, and a cello.
Webern's Opus 28 is in this genre, and he wrote Five Movements and Six Bagatelles in it.
string quartets [accept two violins, a viola, and a cello (in any order); prompt on just "quartet"]