In the German village of Rysum, in East Frisia, a precious instrument is preserved: an ancient organ, built in 1442/1513, which still has most of the original pipes. Lorenzo Ghielmi and the vocal ensemble Biscantores presents a sort of "organ Mass", where organ pieces and liturgical chant alternate according to the practice of the time. A journey between the late Middle Ages and the dawn of the Renaissance – this is how you could describe the musical programme of this CD, set up in collaboration with the musicologist Konrad Küster, which perfectly illustrates the unique sounds of this instrument.