850 – 950 Parallel Organum

850 Tropes and Sequences

871-99 Alfred the Great, King of England

In this generation the practice of creating tropes and sequences began and extemporized singing in parallel fourths and fifths was first described.

Monophony

Trope

A trope was an addition to the established Gregorian chant and usually consisted of

(1) texts added to the old melismas or

(2) new texts with newly composed melodies which replaced the old melismas. Occasionally,

(3) old texts were given new melodies.

The first known composers of tropes were Tuctilo (d.912) and Notker Balbulus (c. 840-915) , monks at the monastery of St. Gall in Switzerland. An early type was the dialogue trope of the Introit which dramatized important feasts.

Sequence

According to Notker, the sequence was originally a text added to the jubilus (the long melisma at the end of the Alleluia) as a mnemonic device. The early form was a single line followed by four to ten double-line stanzas and ending with another single line. They were syllabic with irregular meter and rhythm. An early writer was Notker Balbulus. All tropes and most sequences were banned by the Council of Trent in 1563.

Polyphony

Parallel Organum

Parallel Organum	|-Latin----- chant—vox principalis
	|-Latin----- added—vox organalis

The Musica Enchiriadis (c. 900), with its commentary Scholia Enchiriadis, described three types of parallel organum:

• A new voice was added (extemporaneously), called vox organalis, a perfect fourth or fifth below the original chant, called vox principalis.
  

• One or both of the voices in type 1 could be doubled at the octave in a style called composite organum.
  

• In a third type two voices began in unison, vox principalis sang while vox organalis held the original pitch until they were a perfect fourth apart, and the two voices sang in parallel fourths until the end of the phrase where they returned to unison in a formula called occursus. 
  

Notation

The music of the Musica Enchiriadis was written with the text itself filling in the appropriate spaces on a staff of from four to eighteen lines, roughly like this:

E				Do-
D					mi-ni
C	Sit		o-ri-a
B		Glo-
A				Do-
G					mi-ni
F	Sit		o-ri-a
E		Glo-