Alberti is a convenient figure to whom to trace an early style of sonata movement which developed through Christian Bach and Clementi, and Haydn and Mozart. He fits the case pretty well because he happened to write a number of sonatas for harpsichord alone. But the great influences which, apart from Pergolesi, affected the growth of this triplex form not only in the symphony, but in the sonata as well, emanated from Mannheim in the Upper Palatinate. The orchestra there under the gifted Johann Stamitz had come to be, before the middle of the century, the best in Europe. The two great composers who were associated with it, Franz Xaver Richter (1709-89) and Stamitz (1717-57) himself, did perhaps more than any other composers of the time to strengthen the new form and give it use as a vehicle of lively feeling. Their energy and their success left an indelible impression upon the symphony, and upon the string-quartet. And they made themselves felt upon the pianoforte sonata; in Vienna through the famous pianist-composer, G. C. Wagenseil (1715-1777); in Paris through the young and popular Jean Schobert (d. 1767) already mentioned; and even in London through Christian Bach. Emanuel Bach, who was frequently publishing sets of sonatas in Berlin from 1740 to 1786, rather gradually adopted the new form than contributed to its development. He never quite shook off a conception of music inherited from his father, which was at the time a little too serious to submit wholly to the new influences. Hence, for example, the triplex form is always a little vague in his music. The themes which he employed, though often beautiful and poetic, were not of the distinct and melodious type which was characteristic of the form. The first and second themes were not often clearly differentiated. In fact he frequently inclined towards constructing his movements out of one theme, which dominated them as the opening figure dominated the old binary form. And he very rarely made use of the stereotyped formulas of the harmonic accompaniment, born of the universal tendency towards a melodic or homophonic style. He cannot be closely associated with the developments which took place within the ‘singing allegro,’ preparing it for use in the great sonatas of the Viennese period. These took the form of setting the two themes out of which the movement was constructed distinctly apart from each other, in strong _relief_, so to speak; and of similarly giving the three sections a clear outline, and the movement as a whole a stable balance. The processes by which this was accomplished in harpsichord music may be briefly touched upon. The first theme tended towards simplicity. Already in sonatas of Christian Bach and Jean Schobert a dignified and somewhat declamatory type of melody is favored for the opening. This was usually repeated, that it might be impressed upon the mind of the listener. Often it came to an end squarely in a full tonic cadence.