When Hildegard of Bingen took holy orders as a nun, she was vowing among other things to observe a life of virginity. She apparently saw this state as a sacrifice, but a blessed one. She composed five pieces of music (grouped nearby in the manuscripts of her collected works) in praise and celebration of those whose vows included holy chastity, and her passionate regard bleeds from the pages. Her responsory chant O nobilissima viriditas (O most noble greeness) begins with the foundational belief from the Apostle Paul that virginity for the sake of Christ is a noble undertaking. She further glosses a concept from the early Church Fathers, who viewed virginity as a feature of mankind's pre-lapsarian sanctity in the Garden of Eden: before sins of the flesh, men and women enjoyed the purest relationship with God the Father. Hildegard's poetry also alludes to both Christ and Mary, as both of them share characteristics of a noble green branch. Finally, she invests her poetry with an intense spectral shift: from the cool greeness of the first line, she moves to the radiant golden sunlight, and finally to the deep red passion of the intimate concluding line (rubes, ardes, flamma).

The poetess sets this exquisite text to some of her most expansive music anywhere. Rather than use her favorite musical "key" of the E mode, she sets O nobilissima viriditas in the brighter C mode. She deepens the modal color with alternations between B flat and B natural, as well as slightly more irregular motives. She also is able to invest the modal chant melody itself with a spectral shift: it oscillates between the lower (plagal) range and the higher (authentic). In so doing, the composer expands her melody to encompass the amazing total span of nearly two octaves (later musical theorists would call such a melody the musical equivalent of Hyperbole). At the same time, she expands the music horizontally as well. In many of her responsory chants, the melody remains relatively compact to accommodate the repetitions inherent in the form. In this case, however, she gives in to ecstatic inspiration, and allows a series of lengthy melismas. The concluding one lasts for an unheard-of length of 72 notes; in repetition, this melisma could have been sung three times in full, bringing to life the increasing reddish tincture of her text.

© Timothy Dickey, All Music Guide