=Changes in the Old Dance Form=.—In this evolution, the first half of the dance form was made to consist of a Subject, either thematic or melodic, clearly defining the key, and then a modulating passage, generally freer in its runs and arpeggios, leading up to the point of contrast; and the first section was then repeated. The greatest changes took place in the second half. At first, this consisted in the repeat of the Principal Theme in the contrasting key, and a return to the first key through modulations similar to those in the first section; later, however, since this design gave little opportunity for a display of the composer’s originality, the enunciation of the Subject in the contrasting key was followed by a free passage, which gave ample scope to the composer’s fancy; after which the subject again appeared in the principal key, with a concluding passage in the same key. =Establishment of the Cyclic Form=.—The form as a whole was now practically divided into three sections, and a better balance was given to this division by the omission of the second appearance of the Subject in the contrasting key, and the substitution of other material, either relevant or contrasting. The movement now assumed a cyclic form—a statement, leading to a point of contrast, a free fantasia, and finally the statement, leading to a close. This was practically the course of development of what has been named the Sonata Form, up to the time of Haydn. We are now prepared to consider the especial contributions of composers to this form. =First Printed Clavier Sonata=.—The first printed clavier sonata seems to have been published by =Johann Kuhnau= (1660?-1722). This was in the key of B-flat, and was the last of several pieces in the same volume. In the preface, the author gives a semi-apology for its introduction, saying that he sees no reason why sonatas should not be written for the clavier as well as for any other instrument. This sonata begins with an Allegro, followed by a fugal movement; and in the following Adagio movement, the tendency to put the slow movement into a contrasting key is illustrated, as this is in D-flat major. After another Allegro, there is a _Da Capo_ to the first part.