Sonata Form

Sonata form is a musical structure, developed and standardized through the Classical period, that organizes a movement of music into three principal sections. The exposition introduces the movement's main themes, typically a first theme in the home key followed by a contrasting second theme in a related key; the development reworks and fragments those themes and moves them through a wider range of keys; and the recapitulation restates the exposition's themes but resolves the earlier key contrast by keeping them in the home key. Because it builds a large-scale musical argument out of the tension between contrasting keys and its eventual resolution, sonata form became the standard structure for the opening movements of symphonies, sonatas, string quartets and concertos from the second half of the eighteenth century onward, and it remained influential well beyond the Classical period.