Contribution of the Paris School.—When the Paris school ceased to be of utmost importance to the world of music it had bequeathed to the later schools Measured Music, and its forms of Organum, Motet, Conductus and Roundel, and the use of certain not unpleasing intervals, though occasional consecutive fourths, fifths, and octaves appeared. It was, then, the business of the Gallo-Belgic school to refine these intervals, develop measured music, and so improve and develop these old primary forms, eliminating some and evolving others, as to give the school of the Netherlands, one century later, forms pleasing in intervals and of sufficient unity and design to afford opportunity for the infusion of the emotional. In the matter of intervals much was done to develop and use the old ones, excepting the consecutive fourths and fifths which were abolished never to appear again, and many new, or previously unused intervals, were made use of. In the matter of forms, we hear no more of the crude Organum and Conductus, but a little about the Motet, and nothing at all in regard to the Roundel, as such. It is, however, due entirely to this last form that polyphonic music developed; though we hear no more of the Roundel, we do hear much in regard to the Canon, and the Canon was but a highly developed species of the Roundel.
Imitation and the Canon.—The use of Imitation, as we have seen, gradually became more and more important. The old monks, in the very beginning, imitated melody in the fourth and fifth; at the time of the Paris school these melodies were combined with new ones making Imitation with more than one melody, though the melody underwent no real organic development. Now we see in the inception of the Canon a development of real Imitation of only one melody, but given Variety by use of the devices of Inversion, Augmentation, Diminution, etc. And not only did this occur in the Canon, but we find it also in the other forms, in a freer style, adding materially to the Unity. Imitation is the foundation principle of polyphonic music, and this principle was present in the crude efforts of the old monks, in the more intelligent efforts of the Paris school, and now for the first time, receives, in the Gallo-Belgic school, a partial recognition of its real value, and a commensurate use.
Naumann, History of Music, Vol. I, page 315, extract from a chanson by Dufay. Figure 1 shows the principal melody, figure 2 shows the same at the fifth below. The entire chanson is quoted in Naumann with the various imitations fairly well marked; the student should refer to it.
The Value of Imitation.—We must understand, however, that mere Imitation is in itself not a remarkable phenomenon. We imitate, more or less unconsciously, in all arts, and even in our daily habits; but this would be of no lasting importance did we not take that imitation as a foundation for future development, as did the composers of this school. And in these polyphonic schools the imitation was unintentional, as a definite aid to the structure of a musical idea, until it was seen that the imitation must be confined to one definite idea or melody. It was then that the original treatment of melodic development began, and the various devices for developing a melody, without changing its organic structure, inaugurated. This marked the beginning of a school of musical art, a school of definite, and not chance evolution; or in other words, arrangement and development of the earlier acquired ideas.
A Technical Principle.—A little consideration will show how the principle of Imitation was developed. The first step was to imitate a melody at a lower or higher pitch and sing the two or more versions simultaneously; the next step was to bring in the second and other imitating voices successively, at the same or different pitch; thus making the imitation more prominent. So long as composers confined their efforts to using fixed melodies, they could not go far. When they began to adapt well-known melodies and later to invent their own it became possible to make a lengthy work, this leading to a composition in which each of the accompanying voices imitated the first; sometimes only two voices used imitation, the other having a somewhat free part. A next step was to vary the imitation, by changing the motion of the imitating part; if the melody moved up, the imitating part moved downward and vice versa; sometimes the movement was reversed, the imitation beginning with the last note of the phrase and proceeding to the first; sometimes it was made in notes of smaller value (diminution), sometimes in larger (augmentation). These and other devices were experimented with and worked out by the Gallo-Belgic composers. One readily sees that this is intellectual work, that it puts a premium on cleverness and lays expression aside. Yet the technic of an art must first be acquired and the composers of this period were doing this in working out a system of technic in composition with Imitation as the foundation.
Illustration from Naumann, “History of Music,” page 321, Vol. I, showing at 1 and 2 the principal melody and its imitation, and at 3, imitation and inversion. The student should examine the entire example in Naumann.