Léonin

(fl Paris, c1163-1201). Composer, possibly the ‘Magister Leoninus’ mentioned in 1193 who died in or soon after 1201. According to the 13th-century theorist Anonymous IV, he was the ‘best composer [or singer] of organum’ end compiled a Magnus liber containing two-part settings of the solo portions of graduals, alleluias and responsories for all the principal feasts of the year. The Liber no longer exists in its original form, and although Anonymous IV states that the books of polyphony initiated by Léonin and modified by Pérotin were still being used at Notre Dame Cathedral in Paris in the early 13th century, it is no longer believed that Léonin was choirmaster there. The music of the Liber is an extension of a primary improvisatory tradition, and Léonin should probably be seen not as its composer in the modern sense but as one who encapsulated the increasing inventiveness of singers. It is difficult to determine whether Léonin consistently employed the principles of modal rhythm or whether these were fully developed only by the compilers of the later sources.