8th 1 it must have been almost impossible for an Organist, playing with both hands, to avoid sounding concordant intervals simultaneously: and, when once the effects thus produced were imitated in singing, the first step towards the in- vention of Polyphony was already accomplished. This granted, nothing could be more natural than that the Instrument should lend its name to the new style of singing it had been the accidental means of suggesting ; or that the Choristers who practised that method of vocalisation should be called Organizers, though we well know that they sang without any instrumental accompaniment whatever, and that they were held in high esti- mation for their readiness in extemporising such harmony as was then implied by the term Or- ganum. A Necrologium of the I3th century, quoted by Du Cange, ordains, in one place, that 'the Clerks who organize the "Alleluia," in two, three, or four parts, shall receive six pence ' ; and in another, that 'the Clerks who assist in the Mass shall have two pence, and the four Or- ganizers of the "Alleluia" two pence each.' This 'organization of the Alleluia' meant nothing more than the addition of one single Third, which was sung below the penultimate note of a Plain Chaunt Melody, in order to form a Ca- dence. When this Cadence was in two parts only, it was sung by two Tenors ; when a third part was added, it was sung an Octave above the Canto fermo, by the Voice called 'Triplum' (whence our word Treble) ; the fourth part, a Quadruplum, was added in the Octave above the Organum, thus
In Two Parts.
��In Three Parts.
��tin/. Al - - Quadruplum.
��I" Four Parts.
��On;. Al le - lu - la.
After a time the single Third gave place to a continuous Organum. The earliest writer who gives us any really intelligible account of the method of constructing such a Harmony is Huc- baldus, a Monk of S. Amand sur 1'Elnon, in Flanders, who died at a very advanced age in the year 930, and whose attempts to improve the Notation of Plain Chaunt have already been de- scribed at page 469 of the present volume. It is
i An Organ was presented to King Pepln by the Emperor Con- Itantlne VI. in 797.
VOL. II. FT. 11.
��noticeable that, though the multilinear Stave pro- posed by this learned Musician is mentioned as his own invention, he prefers no claim to be re- garded as the originator of the new method of Singing, but speaks of it as a practice ' which they commonly call organization.' He understood it, however, perfectly ; and gives very clear rules for its construction. From these we learn that, though it is perfectly lawful to sing a Plain Chaunt Melody either in Octaves or doubled Octaves, this method cannot fairly be said to constitute a true Organum, which should be sung either in Fourths or Fifths as shown in the following examples.
�� �In o per - 1 - bus su - is.
� �In Fifths.
@; ^ & ~ ^ ^ = re
� ��Tu Fa - tris sem - pi - ter - nus es Fl - U - us.
When four Voices are used, either the Fourths or the Fifths may be doubled.
��& : ^ <z =g
��In o - per - 1 - bus su - is.
��Tu Pa - tris sem - pi - ter - nus ex Fi - 11 - us.
These two methods, in which no mixture of Intervals is permitted, have been called by some modern historians Parallel-Organum, in contra- distinction to another kind, in which the use of Seconds and Thirds is permitted, on condition that two Thirds are not allowed to succeed one another. Hucbald describes this also as a per- fectly lawful method, provided the Seconds and Thirds are introduced only for the purpose of making the Fourths move more regularly.
��Tu Pa - tris sem - pi - ter - nus es Fl - 11 us.
�� � �y -*>--<&-*?->- -gugLg..^ ^^
� ��Tu Pa - tris sem - pi - ter - nus To the modern student this stern prohibition of even two Consecutive Thirds, where any number of Consecutive Fifths or Octaves are freely permitted, is laughable enough ; but our mediaeval ancestors had some reason on their side. In the days of Hucbald, the Mathematics