This is a fascinating selection of early polyphony from the great 11th- and 12th-century school of Notre-Dame in Paris. Some of it is sacred, with pieces relating to the Christmas season. Two items, the Vespers versicle Benedicamus Domino and the famous Matins responsory Descendit, are examples of three-part organum, with highly florid added parts accompanying a prodigiously slow-moving tenor (the basis of the structure – “holding” it together). Other items fall into the mainly syllabic and homophonic category of conductus, in two, three or four parts, with one single monophonic piece. The male-voice ensemble, with their intriguing title Diabolus in Musica (the tritone), embark upon a voyage of exploration – they go right to the heart of an exciting era of musical development when musicians, notably the leaders, Léonin and Pérotin, were exploring the very essence of sound and the blending of sounds, rhythms and vocal timbres. The recording was made in the magnificent abbey of Fontevraud. But why hadn’t the singers chosen Notre-Dame itself for their experimentation, so as to get nearer to the actual acoustic in which the Magnus liber organi composers were operating? In the 1950s, during an early music conference in Paris, we delegates were privileged to enjoy the personal experience of performing some of this music in the spacious resonance of that building.

It is stimulating to hear the Diabolus cantor intoning with superexcellence, demonstrating the kind of medieval elaboration we believe to have been used by proud singers of the time, anxious to show off their fine voices.