Rex Sempiterne Cælitum From Wikipedia the free encyclopedia Rex Sempiterne Cælitum was a Catholic hymn that was sung in Matins during the Paschal season until 1962.[1] References[edit] ^ Herbermann, Charles, ed. (1913). "Rex Sempiterne Cælitum" . Catholic Encyclopedia. New York: Robert Appleton Company. This Catholic Church–related article is a stub. You can help Wikipedia by expanding it.vte This Latin song-related article is a stub. You can help Wikipedia by expanding it.vte