MENSURAL MUSIC. Mensunl 0' measured music is a term applied to a historica: style of composition in which the tones hors exact relations to each other in regard to length or time. Such a designation and the occasion for it may appear strange, as precise rhythm seems to belong to the essence of music_ This. however, is not the case: there was a period when notes were not exactly measured. and mensural music is a subsequent development from this early practice.
All European music of a higher chancier was originally cultivated in connection with speech or poetry. This is true of the musk of the Greeks as well as the early Christians. But speech is not necessarily rhythmical. Ordinary speech is not so at all, and even poetry is not always characterized by the exact time relations typical of strictly measured music. A trochee can be delivered either in two or three part time, the accented syllable matching the un accented in duration or requiring double as much time. And in impassioned utterance rhythmical relations are apt to be lost sight of altogether. Moreover, any rhythm which the accompanying tones may possess would be theirs only by virtue of the words to which they are added: it would be a rhythm of the poetry, not of the music.
Such was the case in Greek music. Al though instrumental performances were also in vogue among the Greeks, music with them, as we have said, was primarily vocal. We know little of its exact character, but are probably justified in regarding it as a species of recita tive, the words guiding the course of the tones. In Christian times the earliest fixed type of the art was the Ambrosian chant, formulated by Saint Ambrose of Milan in the 4th century. This, too, was similar to Greek music in its adherence to the rhythm of the words. A change was wrought by Pope Gregory the Great, two centuries later. What distinguishes his chant from the Ambrosian is supposed to be the uniform length of its tones, giving it a character similar to that of our choral. How ever, this is probably true only in part. Ac cording to the historian Ambros, the sections of the chant which were sung by many voices may have been measured and regular, but the utter ances of the priest must have retained much rhythmical variety. The real difference is formulated by him as follows: °The Ambrosian chant was based essentially on the poetical metre, the Gregorian on the musical.)) What ever the exact nature of the difference, how ever, there is no doubt that Gregory effected a liberation of the tones from the rhythmical shackles of the words. And this was a gain of far-reaching importance. Music had now won its independence, and the way was prepared for the development of mensural composition.
The more immediate occasion for this de velopment was the introduction of harmony. Just as music had primarily been vocal, so also it had been unisonal in character. Though a second tone may occasionally have been added to the principal part, nothing like the later polyphony was attempted. In the 9th century, however, the so-called Organum of Hucbald makes its appearance. In this the theme is systematically accompanied by one, two or three other voices, singing intervals of a fourth, fifth and octave is parallel motion. The point
was now reached beyond which no further ad vance was possible without an exact designa tion of the length of the notes. As long as the singing had been confined to a single person this was not necessary. Nor was it necessary in the case of several persons chanting in unison, if the length of the notes was regu lated by the natural accent of the words, or if all the tones were of equal length. In the Organum, however, a certain care was already required. The singers had to stand so that they could see as well as hear each other, and one among them acted as leader, introducing the new notes at the proper moment. The Or ganum now developed in various directions. There was a more independent progression of parts, contrary alternating with parallel mo tion, and the tones no longer coincided with each other note for note, but one voice sang two or more tones while the other sang one. Manifestly this required an understanding as to the relative duration of the tones, and a method of designating the differences graphically. The first person to formulate the solution of this problem was Franco of Cologne, who lived about the year 1200. Previous to him tones of two lengths, the longa and brevis, had already been recognized. He also admitted the duplex longa or maxima,— twice as long as the longa, and the semi-brevis,— half as long as the brevis. The notes in question were represented as follows: Rests were also indicated by Franco, by means of appropriate signs. The bar-line was not yet in use, hut measure was recognized, being at first confined to triple or time. Duple or time was only permitted at a later date.
There were many complexities in the sys tem as promulgated by Franco and his follow ers. Thus the length of the notes was not only determined by their own character and appear ance, hut also depended on the neighboring notes. There were °alterations') and l'imper fections,° aprolations° and °ligatures,'" but space will not permit us to enter into all these involved details, which have only a remote his torical interest. The rules governing mensural music were further elaborated — among other writers —by Marchettus of Padua, who lived about a century after Franco; and Jean de Muris, a celebrated theoretician of the 14th century. Notes of shorter duration were grad ually introduced, such as the minima, semi minima, fusa and semi-fusa. And the notation too was modified, until it finally assumed the appearance to which we are accustomed to-day. Together with the Organum, mensural music furnished the basis for all subsequent advances in the art. It was the indispensable prerequisite for the growth of rhythmical and contrapuntal variety. It made possible the wonderful de velopment in part writing which was soon to take place in the Netherlands, and which was eventually to lead to the glories of modern instrumental and choral music. In fine, it may he regarded as one of the two or three great elementary contributions to the art, on which the dazzling superstructure of modern beauty and inspiration has been erected.