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 whichPhilip Emanuel Bach left it, and to crystallize it as a structural type for all time.
Among the most important advances made by Haydn over the practice of his predecessor, as we saw it illustrated in the last chapter, were (1) the greater importance and individuality given to the second theme[26]; (2) the abolishment of merely rhapsodical passages, and the substitution of successions of chords marking off unmistakably the various sections of the movement; (3) increased definition at the end of the exposition section, in the "codetta," which, in some instances, even has a definite theme or themes of its own, called conclusion-themes; (4) greater clearness in the key-system of the whole movement, according to the principle of Duality-Plurality-Unity already discussed; (5) increased importance and extent of the coda, which sometimes grows to the proportions of a fourth section to the movement; (6) use of an introduction, generally in slow time and of a stately character, preparing the mind for serious attention. It will be noted that all these advances are in the direction of making the form more definite, clear-cut, and readily intelligible, as it was most important that it should be made in its early existence until it was perfectly familiar to the audience. Increasedvarietycame later, in the work of Mozart and Beethoven, and could come only after the typical structure was thoroughlyunderstood by the public. Thus Haydn's function was that of a systematizer, an establisher of sure foundations on which more elaborate and free superstructures may later be built; and for this work his clear, simple, well-disciplined mind and his thorough rather than brilliant artistic technique admirably fitted him.
These points will be made clear by an analysis of an example of sonata-form, taken from the "Surprise" Symphony which he wrote for London audiences in 1791, toward the close of his career.
The general structure, as regards both themes and larger sections, may be conveniently shown in tabular form, thus:—