During the period when the polyphonic writers were pouring out their most glorious and living stuff, in the first lame, crude fugues the medium was being prepared for the triumphs of Handel and Bach; and in the same way, while Bach was writing the G minor and A minor fugues (I am not speaking of vocal music) some smaller men were working at what was destined to grow into the symphony, sonata and quartet. These terms are used here in their present-day signification. In the seventeenth and eighteenth centuries such words as symphony and overture, and suite and sonata, were interchangeable; but that does not at all concern us here. The symphony or sonata or quartet form is what these early groups of movements led up to. That these groups of movements originated in the theatre is quite probable; this is indicated by the mere fact that the word "overture" was frequently used to describe them. When the fugue was in its fullest maturity composers were turning overtures out in vast quantities. Our own Arne tried his hand at them, and no one looking at _his_ would dream that the sonata form was so nearly ripe at the time. Emanuel and Johann Christian Bach wrote them, and from these two Haydn got the hint which he turned to such splendid account. Abel, Stamitz and Wagenseil wrote them, and achieved nothing in particular. These groups consisted of three or four movements, and we need not linger long over them. It goes without saying that all the movements were short; they consisted either of simple tunes or of series of harmonic progressions broken up into figures or patterns. Of real development and climax there is none; of such things as well-defined, characteristic first and second subjects there is little sign. The themes were of the formal mathematical type developed during the fugal period--a type that "worked" easily, and in a way effectively, in the fugue itself, but was unnecessary and, indeed, tiresome when contrapuntal working was not the aim and object. The endless variants on this kind of thing, for example-- [Illustration: some bars of music] were simply a snare, and kept writers from seeing the importance of singing and singable melody in the coming style. To show the difference between the old and the new at once, let me here give two bits of themes from Mozart and Haydn. They are in appearance not so far removed from the contrapuntal type of theme, and while they sing themselves they yet served their inventors capitally for contrapuntal treatment. [Illustration: some bars of music]