Another factor in the development of the new liturgical books and their interpretation is shown in commentaries known as expositio Missae. These works interpreted liturgy in colorful, allegorical ways so that a deeper meaning was seen behind every liturgical detail. For instance, the entrance chant of the Mass was seen as the voice of the prophets foretelling Christ’s coming, the Gloria as the song of the angels heralding Christ’s birth, and the reading of the Epistle as John the Baptist’s proclamation of Christ as the Messiah. Such fanciful interpretations led to changes in liturgical practice, such as the celebrant reciting the canon in a low voice as he was seen in the role of the High Priest alone entering the Holy of Holies of the Temple. Two of Charlemagne’s advisors, Alcuin and Amalarius of Metz were proponents of this allegorical interpretation.
