The Liturgy of the Hours (Latin: Liturgia Horarum) or Divine Office (Latin: Officium Divinum) or canonical hours, often referred to as the Breviary, is the official set of daily prayers prescribed by the Catholic Church to be recited by clergy, religious institutes, and the laity. It consists primarily of psalms supplemented by hymns, readings and other prayers. Together with the Mass, it constitutes the official public prayer life of the Church. Daily recitation of the Liturgy of the Hours is a canonical obligation everywhere for priests and for deacons aspiring to the priesthood; the extent of the obligation for permanent deacons is determined by the relevant episcopal conference. The Liturgy of the Hours also forms the basis of prayer within Christian monasticism.