Tenebræ is the name given to the service of Matins and Lauds
belonging to the last three days of Holy Week. This service, as
the "Cæremoniale episcoporum" expressly directs, is to be
anticipated and it should be sung shortly after Compline "about
the twenty-first hour", i.e. about three p.m. on the eve of the
day to which it belongs. "On the three days before Easter", says
Benedict XIV (Institut., 24), "Lauds follow immediately on
Matins, which in this occasion terminate with the close of day,
in order to signify the setting of the Sun of Justice and the
darkness of the Jewish people who knew not our Lord and
condemned Him to the gibbet of the cross." Originally Matins on
these days, like Matins at all other seasons of the year, were
sung shortly after midnight, and consequently if the lights were
extinguished the darkness was complete. That this putting out of
lights dates from the fifth century, so far at least as regards
the night Office, is highly probable. Both in the first Ordo
Romanus and in the Ordo o