HOURS, CANONICAL, certain portions of the day set apart by rule (canon) of the church for prayer and devotion. The Jewish custom of praying three times a day, i.e. at the third, sixth and ninth hours, was perpetuated in the early Christian Church (Acts ii. 15, iii. I, x. 9), and to these were added midnight (when Paul and Silas sang in prison), and the beginning of day and of night. Ambrose, Augustine and Hilary commended the example of the psalmist who gave praise "seven times a day" (Ps. cxix. 164). The seventh (Compline, Completorium) was added by Benedict. These hours were adopted especially in the monasteries as a part of the canonical life, and spread thence to the cathedral and collegiate chapters.
Since the 6th century the number and order of the hours have been fixed thus : matins, lauds, prime, terce, sext, none, vespers, compline. See BREVIARY.