A Cantata is a musical composition for voice and instrumental accompaniment, usually spanning several movements and involving choral forces. The term has been in use since the early 17th century, when it usually designated a type of single voice madrigal. The cantata eventually evolved into a substantially secular dramatic piece, often indistinguishable from an opera fragment. In the case of religious-themed cantatas, it is hard to tell the difference with a small oratorio, or a fragment of oratorio. Nowadays the term is somewhat loosely employed. Famous pieces in the genre include Bach's collection of more than 200 cantatas, Carl Orff's Carmina Burana and Luigi Nono's 'el canto sospeso'.