Corelli’s works are, leaving aside his personal genius, indicative of the state of the sonata at the end of the seventeenth century. That the sonatas with suite movements were called chamber sonatas and the others church sonatas gives us some hint of the relative dignity of the two forms in the minds of composers of that day. In 1695 J. Kuhnau published in Leipzig his sonata in B-flat for the harpsichord, with the prefatory remarks that he saw no reason why the harpsichord, with its range of harmony and its possibilities in contrapuntal music, should be restricted to the lighter forms of music (such as the suite). He therefore offered to the public a piece for harpsichord written in the more dignified form of the violin music of the day, which he called the _Sonate aus dem B_. Here, as we remarked in chapter I, the word sonata comes into pianoforte music, bringing with it a dignity, if not a charm, which was felt to be lacking in the suite. Kuhnau’s sonata is in four movements, none of which is very clearly articulated. The _adagio_ comes between the second and fourth and is in the key of E-flat major. This sonata was followed by seven more, published the next year under the title of _Frische Clavier Früchte_. The tone of all is experimental and somewhat bombastic. But at any rate we have at last keyboard sonatas. During the lifetime of Corelli two other Italian violinists rose to shining prominence, Locatelli[21] and Vivaldi[22]. To them is owing a certain development in the internal structure of a new form of the sonata called the concerto, of which we shall say more later on. Here we have to note, however, the tendency of both these composers to make their concertos and sonatas in three movements: two long rapid movements with a slow movement between. Corelli left _sonate da camera_ and _sonate da chiesa_ of the same description; but the procedure seems to have recommended itself to Sebastian Bach mainly by the works of Vivaldi, of which, as we have seen, he made a most careful study. Hence we have from Bach not only the beautiful sonatas for violin and harpsichord in three movements, but harpsichord concertos,--many of which were transcriptions of Vivaldi’s works, but some, like the exquisite one in D minor cited in the last chapter, all his own,--likewise on the same plan. So, too, were written many of the Brandenburg concertos, notably the one in G major, No. 5. Finally we have the magnificent concerto in the Italian style for cembalo alone, which is more truly a sonata, leaving for all time a splendid example of the symmetry of a well-wrought piece in three movements.