Before the eleventh century the prayers of the Divine Office were not all contained in one book, as they are now in the Breviary, which is an abridgment or compendium of several books.  The recitation of the Office required the Psaltery, the Lectionary, the Book of Homilies, the Legendary, the Antiphonarium, the Hymnal, the Book of Collects, the Martyrology, the Rubrics.  The Psaltery contained the psalms; the Lectionary (thirteenth century) contained the lessons of the first and second nocturn; the Book of Homilies, the homilies of the Fathers; the Legendary (before the thirteenth century), the lives of the saints read on their feast days.  The Hymnal contained hymns; the Book of Collects, prayers, collects and chapters; the Martyrology contained the names with brief lives of the martyrs; the Rubrics, the rules to be followed in the recitation of the Office.  To-day, we have traces of this ancient custom in our different choir books, the Psalter, the Gradual, the Antiphonarium.  There were not standard editions of these old books, and great diversities of use and text were in existence.

Divisions of the Divine Office.—­How is the daily Office divided?  The Office is divided into the night Office and the day Office.  The night Office is so called because it was originally recited at night.  It embraces three nocturns and Lauds.  The day Office embraces Prime, Terce, Sext, None, Vespers, and Compline.

Parts or Hours of the Office.—­How many parts or hours go to make up the Office?  Rome counts seven, and seven only; and this is the number commonly counted by liturgists and theologians.  They reckon Matins and Lauds as one hour.

The old writers on liturgy ask the question:  “Why has the Church reckoned seven hours only?” Their replies are summarised well by Newman:  “In subsequent times the hours of prayer were gradually developed from the three or (with midnight) the four seasons above enumerated to seven, viz.:—­by the addition of Prime (the first hour), Vespers (the evening), and Compline (bedtime) according to the words of the Psalm—­’Seven times a day do I praise thee, because of thy righteous judgments.’  Other pious and instructive reasons existed, or have since been perceived, for this number.  It was a memorial of the seven days of creation; it was an honour done to the seven petitions given us by our Lord in His prayer; it was a mode of pleading for the influence of that Spirit, who is revealed to us as sevenfold; on the other hand, it was a preservative against those seven evil spirits which are apt to return to the exorcised soul, more wicked than he who has been driven out of it; and it was a fit remedy of those successive falls which, scripture says, happen to the ‘just man’ daily.” (Tracts for the Times, No. 75.  “On the Roman Breviary.”)

“Matutina ligat Christum qui crimina purgat,
Prima replet sputis.  Causam dat Tertia mortis. 
Sexta cruci nectit.  Latus ejus Nona bipertit. 
Vespera deponit.  Tumulo completa reponit. 
Haec sunt septenis propter quae psallimus horas.”