Haydn and Mozart represent an important stage in sonata history: they stand midway between Emanuel Bach and Beethoven. It is usual to look upon Bach as the founder, Haydn and Mozart as the builders-up, and Beethoven as the perfecter of the sonata edifice. Such a summing-up is useful in that it points to important landmarks in the evolution of the sonata; yet it is only a rough-and-ready one. Bach was something more than a founder, while Beethoven, to say the least, shook the foundations of the edifice. Haydn and Mozart would seem to be fairly described, for traces of scaffolding are all too evident in their works, yet they found the building already raised. Some of it, however, appeared to them in rococo style, and so they gradually rebuilt. And they not only altered, but enlarged and strengthened. Of rebuilding and alteration, their slow movements and finales give evidence; and of enlargement, all the three sections of movements in so-called sonata-form. Their subject-matter, as it grew in importance, grew in compass. This in itself, of course, enlarged the exposition section; but the transition passage from first to second theme, and the rounding-off of the section, both grew in proportion. The joints, too, of the structure were strengthened: the half cadence no longer sufficed to divide first from second subject, or, after development, to return to the principal theme; then, again, the wider scope of the development itself demanded more striking harmonies, more forcible figuration, and more varied cadences. The subject-matter, we have said, became more important; it differed also in character. The themes of Emanuel Bach, for the most part, seem to be evolved from harmonic progressions and groupings of notes; those of his successors, rather the source whence springs melody and figuration. The one uttered broken phrases; the others, complete musical sentences. Italian fashion prevailed during the second half of the eighteenth century much as it did in the first. The simple charm and warmth of the music of the violin-composers had penetrated the contrapuntal crust which covered Emanuel Bach's heart; and the feeling that he could never hope to rival his father must have rendered him all the more willing to yield to it. But the influence of his father could not be wholly cast aside, and Emanuel was, as it were, drawn in opposite directions; it is really wonderful what he actually achieved. True lovers of John Sebastian Bach know well that his music, though of a contrapuntal character, is by no means dry; but the formal aspect of it must have made its mark on the son ere he could feel the power, and realise the splendour of his father's genius.