The "Divine Office" or "Liturgy of the Hours" is a set of short services observed 8 times a day. Celebration of the Divine Office began during the Medieval Period and is still observed today in monasteries throughout the world. The services take place approximately every 3 hours. Stucture varies between services, but generally they consist of psalms, prayers, antiphons, responses, canticles and readings. Matins is the first of the 8 Liturgies.