or punct being the name for the written note.  There being now two distinct melodies, both had to be noted instead of leaving it to the singers to add their parts extemporaneously, according to the rules of the organum, as they had done previously.  Already earlier than this (in 1100), owing to the tendency to discard consecutive fourths and fifths, the intermovement of the voices, from being parallel and oblique, became contrary, thus avoiding the parallel succession of intervals.  The name “organum” was dropped and the new system became known as tenor and descant, the tenor being the principal or foundation melody, and the descant or descants (for there could be as many as there were parts or voices to the music) taking the place of the organum.  The difference between discantus and diaphony was that the latter consisted of several parts or voices, which, however, were more or less exact reproductions, at different pitch, of the principal or given melody, while the former was composed of entirely different melodic and rhythmic material.  This gave rise to the science of counterpoint, which, as I have said, consists of the trick of making a number of voices sing different melodies at the same time without violating certain given rules.  The given melody or “principal” soon acquired the name of cantus firmus, and the other parts were each called contrapunctus,[11] as before they had been called tenor and descant.  These names were first used by Gerson, Chancellor of Notre Dame, Paris, about 1400.

In the meantime (about 1300-1375), the occasional use of thirds and sixths in the diaphonies previously explained led to an entirely different kind of singing, called falso bordone or faux bourdon (bordonizare, “to drone,” comes from a kind of pedal in organum that first brought the third into use).  This system, contrary to the old organum, consisted of using only thirds and sixths together, excluding the fourth and fifth entirely, except in the first and last bars.  This innovation has been ascribed to the Flemish singers attached to the Papal Choir (about 1377), when Pope Gregory XI returned from Avignon to Rome.  In the British Museum, however, there are manuscripts dating from the previous century, showing that the faux bourdon had already commenced to make its way against the old systems of Hucbald and Guido.  The combination of the faux bourdon and the remnant of the organum gives us the foundation for our modern tone system.  The old rules, making plagal motion of the different voices preferable to parallel motion, and contrary motion preferable to either, still hold good in our works on theory; so also in regard to the rules forbidding consecutive fifths and octaves, leaving the question of the fourth in doubt.