Hildegard of Bingen composed both poetry and music for an extremely wide variety of liturgical occasions, and in these pieces, she often gave an extremely personal and mystical take on the holy mysteries. She wrote in awe of the heavenly Father and the Son, with reverence and deeply allusive imagery for the Blessed Virgin, with complicated visions for saints such as Disibod and Rupert, who were patrons of her congregations. Yet she also excelled at poetry and music for more "generic" saints of all classes, writing for martyrs, confessors, virgins, and the like. Two of her most powerful generic pieces were for the Apostles who shared Christ's earthly ministry, O cohors militie and O lucidissima apostolorum. In the latter, she wrote text and music in the responsory form, appropriate for singing during a Mass in honor of an apostle. The radiant text of this piece speaks of the "brightest crowd of the apostles," "surging in true knowledge and opening the pens of the devil," "washing away the captives in rivers of living water"; these people are the "immaculate bride of the Immaculate One."

For this powerful Latin text, Hildegard composed a truly extraordinary chant melody. The music opens in one mode: F with explicit B flat pitches; for several phrases the melody seems anchored in this mode, with textual fragments ending on the pitch F and melodic emphasis on that pitch as well as its dominant and upper octave. But on the extended melodic melisma as the text describes the "washing away" of the devil's captives, Hildegard composes a triple melodic sequence that not only rises dramatically in pitch, but also completely shifts the melodic mode upwards to G! Every single melodic phrase thereafter not only cadences on the new tonic of G, a remarkable number of them also include either a G-D-G set of upwards leaps, or a crest on the high third above G, or both. Hildegard's melodic style is often credited with such modally powerful gestures, but it is most typical for her either to use them at the beginning of a piece, strongly to establish the mode, or to gradually expose them as her poetry heats up. Almost nowhere else does she tentatively establish one mode only to solidly conclude in another; it is one of the most powerful melodic gambits she ever wrote, so to embody the sudden freedom enjoyed by those who hear the message of the Gospels!

© Timothy Dickey, All Music Guide