In this movement of C. P. E. Bach, despite its many crudities, there is taken a long step toward the establishment of modern sonata-form. The main divisions of the form, exposition, development, and recapitulation, appear clearly; solid harmonic structure is attained by the sequence of duality, plurality, and unity; there are two contrasting themes, though the second is rudimentary; the general principle of development of themes through insistence on salient features is illustrated; and the whole movement is written in a style well suited to the piano, and emancipated from the influence of polyphony and of the short dance and song forms.
In the next chapter we shall see how Haydn and Mozart proceeded to build more elaborate structures on the foundation thus laid by C. P. E. Bach.
_Dickinson: "The Study of the History of Music," Chapter XIV. Grove: "Dictionary of Music," articles on "Bach, Philip Emanuel," "Sonata," "Form." C. H. H. Parry: "Evolution of the Art of Music," Chapters VII and IX (Appleton). "Oxford History of Music," Volume IV._
[22] It will be noted that there are three names for this one type of structure: "Sonata-form," "First-movement form," and "Developed ternary form."
[23] No. 1 in the edition by Peters, Leipzig.
[24] See Hadow's "Sonata-Form" (Novello) Chapter VII, for a discussion of the various methods of theme-development.
The type of musical structure which first took on definite shape in the work of Philip Emanuel Bach, the type which may be defined as consisting essentially of the exposition, development, and restatement of two contrasted themes, and to which the name of sonata-form is given, was not reduced to perfect clearness until the time of Haydn (1732-1809), who because of his labors in this field is often called "The father of the symphony."[25] Having the inestimable advantage of being concert-master, for a period of thirty years (1761-1791), to the princely house of the Esterhazys, where he had a small but good orchestra under his direction, and was expected constantly to produce new pieces for it to play, he was practically forced to write an astonishing amount of music, in all of which this form figured prominently. Hardly one of his hundred and twenty-five symphonies, and his seventy-seven string quartets, etc., is without one or more examples of sonata-form. Such constant practice enabled him to carry it far beyond the rather indeterminate state in which Philip Emanuel Bach left it, and to crystallize it as a structural type for all time.