Walther, again, in his dictionary
of music,[1] which appeared at Leipzig in 1732, describes a sonata as
a "grave artistic composition for instruments, especially violins."
The idea of grouping movements was already in vogue in the sixteenth
century. Morley in his _Plain and Easy Introduction to Practical
Music_, printed in 1597, speaks of the desirableness of _alternating_
Pavans and Galliards, the one being "a kind of staid musick ordained
for grave dancing," and the other "a lighter and more stirring kind of
dancing." Contrast was obtained, too, not only by difference in the
character, but also, in the measure of the music; the former was in
common, the latter in triple time.

With regard to the grouping of movements, Corelli's sonatas show
several varieties. The usual number, however, was four, and the order
generally--slow, fast, slow, fast. Among the forty-eight (Op. 1, 2, 3,
and 4, published 1685, 1690, 1694, and 1700 respectively) we find the
majority in four movements, in the order given above[2]; of the twelve
in Op. 3, no less than eleven have four movements, but--

No. 1 (in F) has Grave, Allegro, Vivace, Allegro.
No. 6 (in G), Vivace, Grave, Allegro, Allegro.
No. 10 (in A minor), Vivace, Allegro, Adagio, Allegro.

There are, however, eight sonatas consisting of _three movements_; and
as this, a century later, became the normal number, we will give the
list:--

Op. 1, No. 7 (in C) Allegro, Grave, Allegro.
(Middle movement begins in
A minor, but ends in C.)

Op. 2, No. 2 (in D minor) Allemanda (Adagio)
Corrente (Allegro), Giga
(Allegro).

Op. 2, No. 6 (in G minor) Allemanda (Largo), Corrente,
Giga.

Op. 2, No. 9 (F sharp minor) Allemanda (Largo).
Tempo di Sarabanda (Largo).
Giga (Allegro).

Op. 4, No. 8 (D minor) Preludio (Grave).
Allemanda (Allegro).
Sarabanda (Allegro).

Op. 4, No. 10 (G) Preludio[3] (Adagio) and Allegro.
Adagio and Grave (E minor).
Tempo di Gavotta (Allegro).

Op. 4, No. 11 (C minor) Preludio (Largo).
Corrente (Allegro).