The monks of monasteries and the canons of cathedrals attended and sang a series of services called "Offices", which took place throughout the day. The word "Office" means ‘function’ or duty, and most of the clergy devoted the majority of their time to the performance of this ‘duty’, especially in monastic communities. The monastic structure for the Hours was as follows:

In secular churches such as the cathedral of Notre Dame, services were combined into a night service, a morning service, and an evening service. The schedule would be as follows:

 

Solem justitae

This chant would have been heard during Matins on the feast of the Nativity of the Virgin Mary, which takes place on September 8. Matins was the most elaborate of the services in the Middle Ages. Its distinctive feature is a section called 'Nocturnes' which occurs near the end of the service. On high feasts, there were three Nocturnes. Each Nocturne consists of three psalms sung to a reciting tone with a refrain known as an antiphon, a short response called a versicle, and three lessons, each followed by a great responsory which involves alternation between solo singers and the choir. The responsory was, in essence, a sung response to the lesson, with a biblical text or a text from one of the Early Church writings.

Solem justitiae was the responsory which followed the first lesson. It is thought to have been composed in the eleventh century by Fulbert of Chartres, a bishop who was credited for some time with the institution of the Virgin's Nativity Feast at Chartres. He probably also composed the other two responsories used at this Feast.

Great responsories were only heard at Matins. Other services contained short responsories. The more elaborate type heard at Matins begins with a choral respond followed by a psalm verse sung by a soloist. The second portion of the responsory is then repeated by the choir, sometimes followed by part of the Gloria Patri and ending with a third repetition of the last half of the responsory.

In addition to its role in Matins, Solem justitiae was sung at Notre Dame at the Feast of the Nativity of Mary during the procession before Mass. The clergy stopped before the cross at the entry to the chancel and sang in station, just as they did in the procession for the octave of Conception, the feast honoring the Virgin's conception of the Christ-child.


Regina Caeli

Other services of the Office consisted of psalms, readings, hymns, canticles and prayers. The psalms were recited to simple formulas, framed by an antiphon, and the canticles were performed in a similar fashion. Even simpler recitational patterns were used for the readings and prayers. Hymns, with their poetic texts, were basically strophic with each line of every stroph containing the same metrical pattern. Each of these items were important, but the main purpose of the Offices was to provide a framework for the singing of Psalms.

At Notre Dame, the midnight service (Matins/Lauds) was followed at Notre Dame by the antiphon to Mary, Regina Caeli. At first, it was sung only at Easter, but by the fourteenth century, it was sung every day after Lauds. There are three other antiphons, or anthems to Mary. Unlike the antiphons used with psalms and canticles, these are not used as a refrain for a psalm or canticle, but stand as independent items. They were added to the Offices in the eleventh and twelfth centuries, and although churches such as Notre Dame developed their own traditions and employed such items as they wished, generally each of the three other antiphons were used during a specific time of the church year. The other antiphons are: Alma Redemptoris Mater (Gracious Mother of the Redeemer), Ave Regina Caelorum (Hail, Queen of Heaven), and Salve Regina (Hail, Queen).