Marking the Hours


Music for celebrating the Divine Office from the Directoriuvm Chori: Ad Vsvm Omnivm Ecclesiavm Cathedralium & CollegiatarumRare Books Collection, Special Collections Research Center, George Mason University Libraries, M2153.2 .C36 1665

Sunday, November 27th marks the beginning of Advent in the Western Christian tradition. The season of Advent starts the fourth Sunday before Christmas and is preparation for the celebration of Jesus’ birth on Christmas Day. It also marks the beginning of the liturgical year in the Catholic Church.

In the Special Collections Research Center, we have some examples that allow us to see the ways in which people historically celebrated the Christian liturgical year.

Vellum Leaf from a Missal printed in 1493

Vellum Leaf from a Missal printed in 1493, Rare Books Collection, Special Collections Research Center, George Mason University Libraries, BX2015 .A2 1493

In medieval Christian Europe, public worship and the liturgical year revolved around the Mass or the Divine Office.

The Mass can be defined as the rituals, hymns, and readings that evolved around the celebration of the Eucharist.

In contrast, the Divine Office is a set of prayers recited at specific hours of the day. The Divine Office is primarily composed of the biblical Psalms with supplemental hymns and readings. In the Middle Ages, singing the Divine Office was the responsibility of monks and nuns. According to John Cassian (d. 435), “The whole purpose of the monk and indeed the perfection of his heart amount to this–total and uninterrupted dedication to prayer.”(1)

The medieval Divine Office was composed of eight “Offices” or “hours.”

In the Middle Ages, each of these forms of worship (Mass & Divine Office) was celebrated using a different type of book:

  • Lectionary: used by priests, it contains the Scriptural readings for use in Mass
  • Breviary: used by monks, the Breviary was a service book containing the texts necessary to celebrate the Divine Office
  • Missal: used by priests, the missal is a service book containing texts (prayers and instructions) necessary for the performance of the Mass.
  • Gradual: used by priests, it contains the musical portions of the Mass, and omits the spoken parts
  • Antiphoner: used by monks, this book would have been large enough for a monastic choir to see it, and contains sung portions of the Divine Office.

One can see how the emergence of the printing press began to change these medieval books with one of the volumes from our Rare Books collection, the Directorivm chori : ad vsvm omnivm ecclesiarvm cathedralium & collegiatarumThe Directorivm Chori is the first post-Tridentine chant book published in Rome, and it contains the basic elements for singing the Divine Office, including the principal Psalms, hymns, verses, lessons and prayers. Unlike medieval antiphoners, however, the Directorivm Chori is small, meant to be held and viewed by one person–not an entire choir.

To search the rare books collection for more interesting items from our collection, search the Mason Catalog, click on “Set Limit” and limit by the location “Fenwick Special Collections.”

  1. John Cassian, Conferences. Trans. Colm Luibheid. (New York: Paulist Press, 1985) 101


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