Based on the "Conditor Alme Siderum" chant, this piece opens with handbells playing the melody, followed by unison a cappella choir. The organ enters, setting up the assembly response, which alternates with cantored verses. Multiple performance options are included: A choir may end after the opening song, or move directly into a chanted setting of the sign of the cross, Collect, Confiteor, and absolution, closing with a polyphonic Kyrie.
