- James Webster
The most important principle of musical form, or formal type, from the Classical period well into the 20th century. This form is that of a single movement, not a ‘sonata’ as a whole; such a movement is most often part of a multi-movement instrumental cycle such as a sonata, piano trio or quartet, string quartet or quintet, symphony etc., or an independent movement like an overture or tone poem. Sonata form as such is less common in fantasies and the like, small movements, concertos and vocal music, but its principles may influence other features of form in such works. Though most characteristic of first movements in fast tempo, it often appears in middle movements and finales, and in moderate and slow tempo; hence the synonyms ‘sonata-allegro form’ and ‘first-movement form’ are best avoided....