Chamber music includes compositions for a smaller ensemble consisting of two to nine musicians. Beethoven's chamber music is targeted preferably to string instruments, such as string quartets (two violins, viola, violoncello), string trios and string quintets or to a mixed ensemble of string instruments and piano, such as a piano trio (piano, violin, violoncello) or a piano duo (piano plus a string or wind instrument).
Beethoven's wind instrument compositions were nearly all written before 1800 and can thus be regarded as his early works. Close to the end of his life, Beethoven mainly worked on string quartets. However, they were so modern that the audience did not understand them.