Leonin(1135-1201) , was a singer and composer. He was linked with the development of the polyphony. Although his identity is not clear the famous teatrise "Anonymous IV"( 1280) described him as the composers with the most quantity of organa compositions in his era. He worked at the parisine church Maria, todays Notre Dame Cathedral. He worked hard whithin the Notre Dame School. The collection "Magnus Liber Organi" was atributed to him.
"Alleluia Pascha Nostrum"
This is the most famous Alleluia from the collection: "Magnus Liber Organi". This work contains a plainchant from the Easter Mass, with organum duplum, discantus and the motet. There is a constant alternation between poliphony and homophony in this work. The plainchant is evident when the choir sings in unison. The organum duplum is showed when the soloists sing. The discantus-orgum triplum and motet are represented by the soloists when they sing in a measurated rhythm using the clausulae (like a cadenza, closing a section).
There is a particularity of Leonin to put toguether in the same work old and new elements like passages of florid organum with discant clausulae. However he was a positive influence for generations to follow.
. "Léonin." The Oxford Companion to Music. Oxford Music Online. Oxford University Press, accessed January 20, 2014,http://www.oxfordmusiconline.com/subscriber/article/opr/t114/e3934.
. "Magnus liber." Grove Music Online. Oxford Music Online. Oxford University Press, accessed January 20, 2014,http://www.oxfordmusiconline.com/subscriber/article/grove/music/17458.
and . "Ars Antiqua." Grove Music Online. Oxford Music Online. Oxford University Press, accessed January 20, 2014,http://www.oxfordmusiconline.com/subscriber/article/grove/music/01356.