It is usually held in the afternoon or evening, sometimes at the conclusion of Vespers, Compline or the Stations of the Cross, and consists in the singing of certain hymns and canticles, more particularly the 0 salutaris hostia and the Tantum ergo, before the host, which is exposed on the altar in a monstrance and surrounded by not less than ten lighted candles.
The seventh (Compline, Completorium) was added by Benedict.
Compline, technically 9 P.M., but usually combined with vespers, is a prayer for protection during the darkness.
Matins and Lauds (about 7.30 A.M.); Prime, Terce (High Mass), Sext, and None (about 10 A.M.); Vespers and Compline (4 P.M.); and from four to eight hours (depending on the amount of music and the number of high masses) are thus spent in choir.
VESPERS (officium vespertinum), in the Roman Catholic liturgy, that part of the daily office which follows none (nona) and precedes compline (completorium).