In the practice of Christianity, canonical hours mark the divisions of the day in terms of fixed times of prayer at regular intervals. A book of hours, chiefly a breviary, normally contains a version
Opening verse from a Book of Hours Domine labia mea aperies et os meum annuntiabit laudem tuam, c. 1520
Breviary of Beatrice van Assendelft, 1485
Cistercians singing the Liturgy of the Hours at Heiligenkreuz Abbey
Traditionally, monastic communities pray the Divine Office in the choir of the church.
Nocturns is a Christian canonical hour said in the nighttime.
Opening verse of matins
Statue of Saint Benedict of Nursia