After centuries during which the only notated music is Gregorian chant for a single voice, the earliest manuscripts that contain what we would recognize as music in two or more parts appear in the 12th century. One is struck by two things: the fully formed nature of the compositional style, and the amount of information that we would consider essential to performance that is missing from these sources. Upon closer inspection, these repertoires reveal themselves to be the tip of an iceberg that consists largely of an improvised tradition, the notation of which was not considered necessary. Looking further back at treatises on music, we can see that this music, which formed the basis of all the western art music to come, was constructed according to well-understood rules and preferences that could be employed by any educated singer.

Eric Mentzel, Professor of Voice at the University of Oregon, specializes in early music and historically-informed performance. He is also a guest teacher at the Royal Conservatory in The Hague, and is on the faculty of the Medieval Music Summer Course at the Schola Cantorum in Basel, Switzerland, and the Vancouver Early Music Programme in Vancouver, British Columbia. In addition to his teaching and research, Professor Mentzel has an international career as a concert soloist in major festivals and concert venues in Europe, Japan, and Australia. He is the founder of the medieval and Renaissance vocal ensemble Vox Resonat, which has recorded two CDs, and has also been heavily involved in contemporary music.