Organum
Organum is a term generally referring to early forms of Western polyphony, originating and developing primarily between approximately 850 and 1300 AD. It represents a significant development in the history of Western music, moving from monophonic chant towards more complex textures involving multiple independent melodic lines.
Key Characteristics and Development:
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Early Organum (Parallel Organum): The earliest documented forms of organum involved adding a second voice to an existing plainchant melody. This second voice, called the vox organalis, would often run parallel to the original chant, known as the vox principalis, at an interval of a perfect fourth or fifth below. This type of organum, described in treatises such as the Musica Enchiriadis and Scolica Enchiriadis, featured a relatively simple harmonic structure.
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Free Organum: As organum developed, composers began to experiment with greater independence between the two voices. In free organum, the vox organalis was no longer strictly parallel to the vox principalis. Instead, it might move in oblique, contrary, or similar motion, allowing for a richer and more varied harmonic texture. The vox organalis could cross above or below the vox principalis.
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Melismatic Organum (Aquitanian Organum): This style of organum, associated with the Abbey of Saint Martial in Limoges and other centers in Aquitaine, France, featured highly florid and melismatic passages in the vox organalis over a slower-moving vox principalis. The vox principalis, now often referred to as the tenor (from the Latin tenere, meaning "to hold"), sustained longer notes, while the vox organalis engaged in elaborate melodic ornamentation.
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Notre Dame Organum: The pinnacle of organum development occurred at the Notre Dame Cathedral in Paris during the 12th and 13th centuries. Composers such as Léonin and Pérotin further refined organum, creating complex polyphonic works featuring multiple voices and rhythmic modes. Pérotin is particularly noted for his organa for three and four voices (organum triplum and organum quadruplum), representing some of the earliest examples of polyphony with more than two independent melodic lines. This era saw the development of discant clausulae, sections where both the tenor and upper voice(s) moved in measured rhythm.
Significance:
Organum is considered a foundational step in the evolution of Western polyphony. It laid the groundwork for later developments in counterpoint, harmony, and musical form. The innovations that emerged from the organum tradition, particularly at Notre Dame, paved the way for the development of motets, conductus, and other important genres of medieval music. The experimentation with rhythm, texture, and melodic independence in organum established fundamental principles that would shape the course of Western music for centuries to come.