Notre Dame Organum developed into the first known use of polyphony. Many believe that the Organum composed at the French Cathedral in Notre Dame was some of the most important advances in the history of music ever. This was the first time there was two or more independent lines of music at the same time. Obviously, this was very exciting. Finally after thousands of years music was advancing into a thick rich multi-part and multi-rhythmic texture.

Let us first look into the cathedral where all this mystery and wonder was taking place. Notre Dame began having mass in 1163. At this time, this cathedral was arguably the most famous church in all of Europe, because of its architectural beauty. It was also a school for composers who later be remembered as the great contributors of that century. In fact later the new style of mass would create so much chaos that a council would have to be established to decide whether or not to keep the mass or revert to an older monophonic style.

The music of Leonin (c. 1159-c. 1201) and Perotin (c. 1170-c. 1236) and their French contemporaries were very influential composers; their style of Mass was widely excepted and reproduced all over the

In the twelfth and thirteenth centuries, measured organum involved the alternation of organal and discant sections. In the organal section each note of the syllabic/pneumatic section of the chant or cantus firmus was set against up to 40 notes in the second voice. In the discant section each note of the melismatic section of the cantus was set against one to three notes in the second voice.

The conductus, among the most lively and independent compositions of the Middle Ages, grew out of quasi-litugical genres such as the hymn and the sequence, and was a direct descendent of Notre Dame Organum. In a polyphonic conductus, two or more voices sing the same words in essentially the same rhythm. Texts consist of metrical Latin poems, often on sacred themes. Eventually secular texts were used as well, often dealing with current events or moral and ecclesiastical issues.

The evolution of organum follows this scheme.

continent. Leonin and Perotin both worked at the new Paris cathedral of Notre Dame. Leonin's Magnus Liber organi (Great Book of Organum) is for two voices; Perotin's generation explored three- and four-voice writing and introduced greater rhythmic precision, for which a system of notation was perfected even as they composed the music that required it. Little is known about the life of Leonin. The writings of Anonymous IV, an English theorist who worked in the late 13th century, are the only source of information about Leonin. Leonin’s birth and death dates are unknown but it is likely he was working as a composer even before the completion of the Notre Dame cathedral in 1163 and died near the end of the century. He worked in a church called "Beatae Mariae Virginis" and then likely worked as a choirmaster in the completed Notre Dame cathedral in Paris. He is one of the earliest known composers of polyphonic church music known as "organum". Below is a short summary of polyphony in early European music.

Some topics in this essay:
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