 According to the "Grove Dictionary of Music and Musicians", sonata form is "the most important principle of musical form, or formal type, from the Classical period well into the 20th century".As a formal model it is usually best exemplified in the first movements of multi-movement works from this period, whether orchestral or chamber, and has, thus, been referred to frequently as "first-movement form" or "sonata-allegro form" (since the typical first movement in a three- or four-movement cycle will be in allegro tempo).However, as what Grove, following Charles Rosen, calls a "principle"—a typical approach to shaping a large piece of instrumental music—it can be seen to be active in a much greater variety of pieces and genres, from minuet to concerto to sonata-rondo.