ABSTRACT
The only document that gives any information on the place of and circumstances surrounding the origin of the Magnus liber organi is the rather slim report of Anonymous IV. Closely related to the problem of the place of origin is that of the liturgical use of the Magnus liber. Anonymous IV merely says that the Magnus liber was composed as an adjunct to both Gradual and Antiphohary, in other words for both Mass and Office. The difference between one melodic tradition and another is easy to explain. Before proceeding to the investigation of the Magnus liber organi, a number of further considerations require clarification. The fact is that the tenors of all the previously mentioned organa correspond melodically with the Antiphonaries and Full Breviaries of the Paris diocese down to the smallest details, even notationally. Both responsories continue differently, though both verses have the same basic melody.
