7. Florid organum of Aquitaine and Compostela manuscripts.
This more advanced style of organum is in evidence from the early 12th century onwards. It is no coincidence that, for the first time with such a repertory, numerous examples of the style survive fully written out, especially in the manuscripts of St Martial (see Sources, MS, §IV, 3). Despite the fortuitous transmission of the manuscripts, which date from between the late 11th century and the early 13th, their contents may be regarded as representative. They contain 94 two-voice pieces. Of these approximately half are based on a pre-existing melody; the rest have apparently newly written text and melody. Most are non-liturgical strophic songs known as versus, and only a small minority are liturgical chant settings. The distinction that was normally made between organa, conductus, sequences and so on in theoretical writing from the time of the Notre Dame composers onwards had not yet been created, neither had they yet been separated in practical sources. Contrapuntally the melismatic style is clearly predominant over the syllabic.
Very close in style to the Aquitaine repertory are some compositions in the Codex Calixtinus. This was a slightly later manuscript which originated at Santiago de Compostela (see Sources, MS, §IV, 3). It was compiled in its present form about 1170.
We can see very clearly how this type of polyphony developed out of the old organum. It derived specifically from one of the two styles of performance previously embraced by organum: namely, simple note-against-note counterpoint, and a counterpoint whose added voice was ornamented. If all ornamental notes are eliminated, examples of the new organum can be reduced to an underlying counterpoint made up of octaves, 5ths, 4ths and unisons. This counterpoint corresponds to the rules of French discant theory as conveyed consistently in the treatises discussed above. Thus in ex.9, if we allow for the possibility of suspensions from 2nd on to unison and from 6th on to octave – suspensions which were still common in Parisian organum – the basic counterpoint comprises nine 5ths, eight unisons, eight octaves and one 4th. Only on the syllable ‘-po-’ do we have to allow for a couple of extra ornamental notes (assuming the text underlay to be exact). The vox principalis proves to be melodically inviolable even when not borrowed directly from plainchant – doubtless because of the very fact that it did traditionally draw on plainchant. On the other hand the notes of the added basic counterpoint are each ornamented. Thus the progression from one chord to the next which in discant was still a direct step came to be replaced in organum by short bursts of melodic movement in the upper part, causing each note of the vox principalis to be drawn out correspondingly in length.
The new vox organalis unfolded above its vox principalis, moving below it only very occasionally in brief crossing of parts. Because of its exposed position in the texture the upper voice naturally became increasingly prominent. What was originally an added voice became the really essential feature and the vox principalis on the other hand now seemed only to support it. It was for this very reason, as well as because it contained the plainchant melody, that this voice became known by the name of ‘tenor’ in the 13th century. The overall range used for the two voices was initially almost identical. Nonetheless there was a clear preference for different tessituras. Moreover, in the manuscripts the use of different clefs clearly distinguished lower voice from upper.
The notation of the two voices was laid out in score and this remained the rule until the end of the Notre Dame era. Initially, at any rate, this arose out of practical considerations in performance. In particular, the length of each single tenor note could only be gauged by the length of the melisma in the upper voice above it. Apart from this the phrasing of melismas in performance was conditioned very much by the harmonies they made with the tenor. For organum throughout most of the 12th century was still not thought of as unique and definitive. Rather it came into being as a result of collaboration between the person who wrote it down – the notator – and the person who actually performed it – the cantor. Thus it still retained, in spite of being written down, a strong element of improvisation.
One fact in particular marks this organum out from all improvised forms of organum: that when stripped of all ornamentation the succession of its underlying harmonies very rarely makes independent sense as satisfying progressions, that is, the result does not accord with the laws of discant. In other words, the melismas are essential to harmonic coherence. Here, then, is a further sense in which the melismatic voice achieves independence. The underlying harmonies seem little more than aids to the performers, insofar as they can be determined with any certainty at all, and insofar as the word ‘harmony’ is legitimate. As such they make possible, and justify, the union of the voices in a new totality. But their progressions show little sign of obeying predetermined rules, just as the melismas show little sign of exploiting certain harmonies and avoiding others. Rather the opposite: within the course of a phrase the intervals that are concordant with the tenor tend not to be approached directly but are delayed. They are reached irregularly and in an almost casual manner. The voices then come together in consonance all the more clearly in the cadences.
Despite the freedom of ornamental movement and the free choice of harmonies, there are nonetheless a number of short, distinctive melodic formulae and turns of phrase that occur frequently (see in this connection Centonization). These consist of only a few notes and can be made to pivot around a central note or to span across an interval. Accordingly, melismatic groups of notes are still relatively short: up to ten notes, but on average only three or four to one tenor note. Despite this, the groups are marked off with vertical strokes at the ends of sections, these corresponding to ends of words or groups of words; they are generally also marked off with strokes between syllables. These strokes are a practical aid in performance, and serve also to show up the structure of the music clearly.