Page "Organum" Paragraph 20

Perotin " is the best composer of Discantus ," according to Anonymous IV, an English student, writing ca. 1275, who has provided at least a few morsels of factual information on Paris Organum and its composers.

Perotin further developed discantus in three part Organum ( Organum Triplum ) where both organal voices are in discantus.

Note that organum purum is not possible in three-part organa, all three parts are modal and need to be organized according to the rhythmic modes.

Perotin even went as far as composing two four-part organa ( quadrupla ), Viderunt omnes and Sederunt principes which were performed in Notre Dame in 1198 on New Year's Day and in 1199 on the feast of St. Stephen ( a decree of Odon de Sully, Bishop of Paris, exists which stipulates the performance of ' organa tripla vel quadrupla ') Apart from organa, Perotin extended the form of the Aquitanian Versus which was henceforth called conductus.

Any conductus is a new composition on new texts and is always composed in the rhythmic modes.

Perotin set several texts by Philippe le Chancelier, while some texts refer to contemporary events.

Two-part conductus form the larger part, though conductus exist for one to four voices.

Three and four part conductus are, by necessity, composed throughout in discantus style.

As in organa tripla, handling three voices ( or four ) precludes the kind of rhythmic freedom found in dupla.

In conductus the distinction is made between ' cum littera ' and ' sine litera ', texted sections and melismatic sections.

The texted parts can sometimes go beyond the modal measure and then fall back in to regular mode in the melismatic section.

Again according to Anonymous IV, Perotin wrote a number of replacement clausulae from organa dupla by Leonin.

As the tenor in Leonin's organa dupla in discant sections proceeds always in the 5th mode ( all longs in a rhythmic group ordine ), Perotin, who was a generation removed from Leonin, saw fit to improve them by introducing different modes for the tenor and new melodic lines for the dupla, increasing the rhythmic organization and diversity of the section.

However, in the largest compilation of Notre Dame repertoires ( F ) no less than 462 clausulae exist, many recurrences of the same clausulae ( Domino, et gaudebit in variant settings, according to Waite ' written in a variety of styles and with varying competence ' A further innovation was the motellus, to be found in W2, in which the upper part of a discant section is supplied with a new text, so that when the tenor utters a single syllable of chant, the upper part will pronounce several syllables or words.

As such it reminds of the prosulae that were composed, replacing a long melism in a chant with new, additional words.

This would have been the first instance of two different texts being sung in harmony.

In turn, the motellus gave birth to the motet which is a poly-textual piece in discant, which obviously sparked a lot a creativity as it soon became a prolific form of composition.