While it is typically used in the first movement of multi-movement pieces, it is sometimes used in subsequent movements as well—particularly the final movement. The teaching of sonata form in music theory rests on a standard definition and a series of hypotheses about the underlying reasons for the durability and variety of the form—a definition that arose in the second quarter of the 19th century.[5] There is little disagreement that on the largest level, the form consists of three main sections: an exposition, a development, and a recapitulation;[6] however, beneath this, sonata form is difficult to pin down in a single model.