Creator Alme Siderum is a setting of the anonymous ninth-century Advent vespers hymn, for a cappella SATB choir, written for the Stanford Service of Lessons and Carols. The piece is notated in 4/4, but every fourth measure it broadens into 6/4, which functions as a metric expansion, almost like a notated fermata. This pattern recurs across the work, dropping out on occasion but returning. In D major, it opens with the men intoning the chant melody, then the women. The music then unfolds into harmonization, with section trios at e Virginis (“from the virgin’s shrine,” for soprano, alto, and tenor) and intacta (“intact,” for alto, tenor, and bass) set apart. A dramatic change comes at Cujus potestas gloriae (“you whose glorious power”), marked forte and appassionato declaring the power of the name of God. A sweeping ritardando into a B-major cadence set low in every voice at curvantur genu depicts the trembling knee bending, rendered in the descent of the voices. The music then moves reverently to F-sharp minor for Te deprecamur (“we beg you”), building a long crescendo, marked implorante, to defende nos ab hostibus (“defend us from the enemy”). The doxology returns to D major and recalls the opening chant theme, an offset soprano descant floating over the unison lower voices before blooming into full harmonization. A deceptive cadence on the mediant F-sharp major lifts the final saeculorum saecula (“forever and ever”). A gentle, chant-like Amen closes the work in the home key.

The audio sample begins at measure 8, with the upbeat to the women’s chant. Here are the Latin and English texts:

Creator alme siderum, aeterna lux credentium, Jesu, Redemptor omnium, intende votis supplicum.	Dear creator of the heavens, eternal light of the faithful, Jesus, redeemer of all, hear the prayers of your supplicants.
Qui daemonis ne fraudibus periret orbis, impetu amoris actus, languidi mundi medela factus es.	You who, in an impassioned act of love, made the weak world healed, lest the earth be lost to demonic offenses.
Commune qui mundi nefas ut expiares, ad crucem e Virginis sacrario intacta prodis victima.	You who, an intact victim, proceeded from the virgin’s shrine unto the cross, to atone for the common world’s sin.
Cujus potestas gloriae, nomenque cum primum sonat, et caelites et inferi tremente curvantur genu.	You whose glorious power, that at first sound of your name, every trembling knee bends, both in heaven and below.
Te deprecamur, ultimae magnum diei Judicem, armis supernae gratiae defende nos ab hostibus.	We beg you, great judge of the ultimate day, defend us from the enemy with the protection of your supernal grace.
Virtus, honor, laus, gloria Deo Patri cum Filio, Sancto simul Paraclito, in saeculorum saecula.	Virtue, honor, praise and glory to God the Father with the Son, likewise to the Holy Comforter, forever and ever.
Amen.	Amen.