Authentic Modes Plagal Modes To suppose that the chant in this period was sung exactly as it appears in the office books of the present day would be to ignore a very characteristic and universal usage in the Middle Age. No privilege was more freely accorded to the mediaeval chanter than that of adding to the melody whatever embellishment he might choose freely to invent on the impulse of the moment. The right claimed by Italian opera singers down to a very recent date to decorate the phrases with trills, cadenzas, etc., even to the extent of altering the written notes themselves, is only the perpetuation of a practice generally prevalent in the mediaeval Church, and which may have come down, for anything we know to the contrary, from remote antiquity. In fact, the requirement of singing the notes exactly as they are written is a modern idea; no such rule was recognized as invariably binding until well into the nineteenth century. It was no uncommon thing in Händel’s time and after to introduce free embellishments even into “I know that my Redeemer liveth” in the “Messiah.” In the Middle Age the singers in church and convent took great merit to themselves for the inventive ability and vocal adroitness by which they were able to sprinkle the plain notes of the chant with improvised embellishments. “Moreover, there existed in the liturgic text a certain number of words upon which the singers had the liberty of dilating according to their fancy. According to an ancient Christian tradition, certain chants were followed by a number of notes sung upon meaningless vowels; these notes, called neumes or _jubili_, rendered, in accordance with a poetic thought, the faith and adoration of the worshipers who appeared to be unable to find words that could express their sentiments. These vocalizations or embroideries were sometimes longer than the chants themselves, and many authors complained of the importance given to these vocal fantasies.”[57] Among the mnemonic signs which, before the invention of the staff and notation system, indicated the changes of pitch to be observed by the singer, there were many that unmistakably point to the traditional flourishes which had become an integral element in the Plain Song system. Many of these survived and were carried over into secular music after the method of chanting became more simple and severe. Similar license was also practised in the later period of part singing, and not only in the rude early counterpoint of the thirteenth and fourteenth centuries, but even in the highly developed and specialized chorus music of the sixteenth century, the embellishments which were reduced to a system and handed down by tradition, gave to this art a style and effect the nature of which has now fallen from the knowledge of men.