The music had shifted from a major key—bright, open, and resolving—to a minor key. "Visually, a minor key often looks 'darker' on the page because of the accidentals. You see more black ink. The composer introduces rhythmic complexity here. The bass line is no longer holding long chords; look, it’s moving. Running notes."
Sanctus, Sanctus, Sanctus... Libera me, Domine, de morte aeterna. (Deliver me, Lord, from eternal death.) sanctus libera sheet music