Chapter 5
The Middle Ages
The Evolution of
Polyphony
Key Terms
Organum
Melismas
The Evolution of Polyphony
Sensuous quality of two or more melodies
must have appealed to listeners
First used c. 900 C.E. as improvised
embellishment to plainchant—organum
Started by adding new melody
(counterpoint) below chant
• One note in counterpoint for each note of chant
(note-against-note)—still free chant rhythm
• Used parallel motion, keeping same interval
between voices
The Evolution of Polyphony
Soon the counterpoint moved more freely
• Moved up or down, no longer parallel
• Still note-against-note, free chant rhythm
By 1100, counterpoint added above chant
in a more flexible rhythm
• Counterpoint moves up or down freely
• Counterpoint adds one, a few, or many notes
for each note of the chant
• Composers begin to write out a counterpoint;
no longer improvised only
The Evolution of Polyphony
By about 1200 composers added one, two,
or three counterpoints to a chant melody!
Organum’s growing sophistication forced
composers to invent rhythmic notation
Composers at Notre Dame Cathedral
developed a system for notating definite
rhythms in a fixed meter
Growth of composed, notated polyphonic
music was a landmark in Western music
Notre Dame School
Flourished during the years the cathedral
was being built, 1163-1235
Developed the first well-understood
system of rhythmic notation
• Based on repeated rhythmic patterns,
analogous to poetic meter
Most important composers were Master
Léonin and Master Pérotin
Pérotin famous for his organa in three and
four voices
Pérotin, Organum
Adorns a plainchant melody from the
Mass, “Alleluia. Diffusa est gratia”
Plainchant used where choir would
normally sing
Organum used in verse, where cantor
would normally sing
Lowest voice sings chant melody, but
using long, slow notes
Upper voices add new melodies with a
gentle triple-time lilt
Pérotin, Organum
• Legato melodies move mostly by step
• Based on a medieval mode (Mixolydian)
• Rich, open harmonies, especially on strong
beats
• Chant portions nonmetrical; organum triple
feel (compound meter) at moderate tempo
• Polyphonic music: faster moving voices over
slow-moving tenor line
• Sung by male voices
• Alleluia chant returns at end, otherwise free