Whether or not a composer called Perotinus Magnus really existed cannot be clearly resolved. However, this name is a synonym for one of the most drastic developments of the occidental music history. As far as is known the works of “Perotinus” are the first four-part compositions and therefore the first notations to accommodate the improvised Gregorian chant into a severer system. This outstanding film of Uli Aumüller revolves around the inscrutability of the French master. On the one hand you see an elaborate setting of pictures reflecting the opulent music presented by the Hilliard Ensemble. On the other hand you see four Perotin experts in a passionate arguing, trying to point out their approach to the medieval times and their attempt to reveal the mystery of one of the most important figures in music history.