The sonata in its main classical significance is a work for one or two instruments consisting of a group of movements, four movements being the full scheme; the last movement in the same key as the first; each movement normally in one tempo, complete in design, independent from the other movements in themes, but aptly related to them in key and style; and constructed in the sonata forms. Though, since the time of Bach (when trios were called sonatas), the term is not applied to works for more than two instruments, the full (and even the normal) characteristics of this most important of all instrumental art-forms are rarely revealed except in trios, quartets, &c., and symphonies. A movement is a piece of music forming a complete design, or at least not merely introductory; and within such limits as either to contain no radical change of pace or else to treat changes of pace in a simple and symmetrical alternation of episodes. The first complete movement of a sonata seldom leads without break to the others, except in modern examples; but the later movements are often connected.
The sonata da chiesa, generally for one or more violins and bass, consisted normally of a slow introduction, a loosely fugued allegro, a cantabile slow movement and a lively finale in some such binary form as suggests affinity with the dance-tunes of the suite. This scheme, however, is not very clearly defined, until the works of Johann Sebastian Bach and George Friderich Handel, when it becomes the sonata par excellence and persists as a tradition of Italian violin music even into the early 19th century in the works of Boccherini.
The sonata da camera consisted almost entirely of idealized dance-tunes. By the time of Bach and Handel it had, on the one hand, become entirely separate from the sonata, and was known as the suite, partita, ordre or (when it had a prelude in the form of a French opera-overture) the overture. On the other hand, the features of sonata da chiesa and sonata da camera became freely intermixed. But Bach, who does not use those titles, yet keeps the two types so distinct that they can be recognized by style and form. Thus, in his six solo violin sonatas, Nos. 1, 3 and 5 are sonate de chiesa, and Nos. 2, 4 and 6 are called partitas, but are admissible among the sonatas as being sonate da camera.
The sonatas of Domenico Scarlatti are a special type determined chiefly by those kinds of keyboard technique that are equally opposed, on the one hand, to contrapuntal style, and, on the other hand, to the supporting of melodies on a lifetess accompaniment. Longo's complete collection of Scarlatti's sonatas shows that, short of the true developed sonata-style, there is nothing between the old sonata da chiesa and Beethovenishish experiments in unorthodox 'complementary keys' that Scarlatti does not carry off with a delightfully irresponsible "impressionism" that enables him to be modern in effect without any serious modern principle. Great, however, as the variety of his forms is now known to be, and numerous as are the newly published slow movements, the normal Scarlatti sonata is that which the concerl-player popularizes; fireworks in binary form, with a perfunctory opening, a crowd of pregnant ideas in the complementary key, and, after the double bar, a second part reproducing these ideas as soon as possible in the tonic. The sonatas of Paradies are mild and elongated works of this type with a graceful and melodious little second movement added. The manuscript on which Longo bases his edition of Scarlatti frequently shows a similar juxtaposition of movements, though without definite indication of their connexioii The style is still traceable in the sonatas of the later classics, whenever a first movement is in a uniform rush of rapid motio1s, as in Mozart's violin sonata in F (Kochel's Catalogue, No. 377), and in several of Clementi's best works.
See also: sonata form