One of the many challenges of working with liturgical sources - not only fragments but also complete survivals - is the condensation of information that takes place on the liturgical page. Books containing liturgical material were intended to provide the texts for a wide range of feasts with various degrees of completion. Certain types of books contained only certain chants, such as the antiphonary, so named for its predominant focus on the antiphons, a text sung before and/or after the psalms and, in the case of a saint's feast, often containing material specific to the saint of the day. In other cases, books that contained several types of texts, such as breviaries, could be divided so that one breviary contained the material for the summer season and the other contained the material for the winter season.
Another type of challenge that comes with the compression of information on the liturgical page, is to be able to identify a text when the only identifying feaure is the first word, the so-called incipit. Thanks to the work of numerous academics, there are great databases in place to help identifying chants, such as cantusindex.org and cantus.uwaterloo.ca. Even when the chant is identified, however, there sometimes remains a question of the chant's intertextuality: What does the chant point to, what texts are it meant to invoke?
RARA Musik M 4
One example of such intertextuality can be found in the fragment RARA Musik M 4, as seen above. The picture shows a section from the office for the feast of the dedication of a church. This was a feast held on the anniversary of the church's dedication, and the date itself therefore varies from church to church, but the texts were for the most part common to all Latin churches.
The picture shows a responsory, a text which follows the lesson and serves as a response to the theme of the lesson, hence the name. Only the incipit is recorded, but this is also all that is needed, as this is a case of biblical intertextuality that would be well known to most of the literate members of the clerical community. The incipit refers to the exclamation of Jacob after he has wrestled the angel in Genesis 28:17, saying "terribilis est, inquit, locus iste, non est hic aliud nisi domus Dei, et porta caeli", which in the Douay-Rheims edition is translated as: "he said: How terrible is this place! this is no other but the house of God and the gate of heaven". Jacob then takes the stone that served as his pillow during the night, sets it erects, pours oil on it, and renames the place Bethel (previously called Luza).
This quotation should also indicate very clearly why this text is used in chant for the feast of the dedication of a church: When Jacob utters his exclamation, he locates on earth a locality that serves as the house of God, a place where the divine presence is particularly strongly felt. In Christianity, the church is exactly such a place, a house of God where mankind can more easily contemplate and become aware of God and the divine mystery. In this way, Jacob's words, as well as his dedication of Bethel onto God, becomes a typological forerunner for every single church in Christendom, and in singing the responsory Terribilis est, the clerical community binds its own church typologically to Bethel, to the proto-church of the Old Testament, and in this way makes itself a part of the long history of Christendom.