The Development of Tonality and Musical Form in the Seventeenth Century

In an opera a soloist was accompanied by supporting harmonies, not by equally important counterpoints.  This resulted in a greater interest in chords and a development of the harmonic style of writing.  The emotional effect of discords in Monteverdi's operas has been referred to on p. 109.

    Again, in an operatic solo the accompanying parts had the same phrase Iengths as the soloist, instead of interweaving parts with overlapping phrases, as in a madrigal.  Modern ideas of phrase balance and cadences at regular intervals resulted from this.  

    The old modes were not so suited to harmony as are the major and minor scales, and they gradually died out during this century.  The feeling for tonality that developed with the use of the major and minor scales led naturally to the art of modulation, which is an essential element in modem musical form.  

    Harmony in major and minor keys, with regular phrases and cadential endings, and modulation to related keys from a key centre, made possible the developments in musical form which are described in Chapter Seven.  Binary form was mostly used for short movements, with rondo form or ritornello form for longer ones.  The aria da capo form appeared occasionally in instrumental as well as in vocal music.  The instrumental music of the seventeenth and early eighteenth century paved the way for the great developments, which were to occur in the days of Haydn, and all can ultimately be traced back to the birth of opera as the root cause.