Senn, Frank C. "Chapter Six: Medieval Liturgical Deteriorization." Christian Liturgy: Catholic and Evangelical. Minneapolis: Fortress Press, 1997, 211-239.
Senn takes the monastic piety of the 9th-11th centuries to have drawn a focus on introspective aspects of Christianity and to have eroded the centrality of corporate, liturgical piety (Senn 1997, 211). With this shift in emphasis, the Church as a whole saw a reduction in unity across cultural, economic, and occupational lines. Senn notes that the liturgical changes can be seen in architecture. He describes the Romanesque church design which spread through Europe, with features of the early Roman basilicas (Senn 1997, 213). By the 12th century, construction of buttresses and other framework allowed for more flexibility in walls, windows, and roofing (Senn 1997, 214), and Gothic architecture became favored. The flexibility inherent in the Gothic architecture allowed for multiple rooms which could house different groups independently. This is precisely what Senn describes, seeing the corporate liturgy decline in importance (Senn 1997, 215). Senn describes the ongoing development of some prominent cathedrals, noting that features were added over time to allow for various functions.
The Gothic period also saw development in music, with the growth of polyphony and the insertion of repetitive tropes into existing sung liturgy (Senn 1997, 218). Senn takes these developments as tending to clutter the liturgy. The insertions may distract from the historic emphasis of the worship (Senn 1997, 219). Senn observes that liturgical drama was also gradually introduced. This became popular outside the liturgy as well, so religious drama came into community life by the end of the tenth century (Senn 1997, 220-221).
Senn observes that from the Carolingian period, priests had prayers to be engaged in at various points in the services. This pulled the priest away from participation in the liturgy. Architecture further separated him from both the choir and the congregation (Senn 1997, 221).
Additional fragmentation of the congregation occurred as private masses for the dead or others became more popular (Senn 1997, 222). In the 8th and 9th centuries many of these were performed by a priest without any assistant or congregation, which explains the presence of many altars in some churches. This also led to the "utter liturgical novelty" (Senn 1997, 222) of spoken masses. The spoken form could proceed more quickly.
During the same period, people received communion less frequently. Senn views this as the result of ascetic practices and insistence on confession and absolution (Senn 1997, 223). Some, who desired the eucharist, would develop a eucharistic cult in which it was celebrated outside of the normal liturgy. These eucharistic cults led to the processions, most notably, the Corpus Christi procession (Senn 1997, 224). The sacrament therefore became something to observe. The emphasis was no longer on partaking of Christ's body and blood (Senn 1997, 226).
Senn continues by describing the separation in time of baptism and first communion, which was related to the fear that the consecrated wine could be desecrated by an accidental spill. Children would not receive communion until they could reliably eat the bread. The cup was reserved for the priest (Senn 1997, 226-227).
The Middle Ages also saw developments in practices of confession and absolution. Senn finds that attitudes of effective contrition moved from the visible, to the internal, and back to the visible during the Middle Ages. Penitence was always recognized as leading to forgiveness. Recognizing penitence was the challenge (Senn 1997, 228). Senn describes numerous writings about the nature of penitence.
In the late Middle Ages, the Missal, a book which contained all the liturgical texts needed for the liturgy, was developed. This allowed one minister with one book to celebrate the mass (Senn 1997, 230). Senn observes this as an extension of the private mass practices to all masses, and a move which rendered the congregation into passive spectators (Senn 1997, 231). As the missal served the mass, the breviary served the same function for the daily offices. This observation leads Senn into a discussion of the various types of churches and functions of clergy by the close of the Middle Ages. He notes that for many the singing of the Daily Offices became an incomprehensible process due to the many inserted tropes and sequences. Further, it became a matter of lawful obedience rather than devotion (Senn 1997, 235).
Despite the challenges Senn notes, with the breaking down of the liturgy in churches, there was participation on the popular level. People would find ways to express their devotion to God in the context of the Church (Senn 1997, 236). There were devotions, particularly centered around prayers of a rosary or contemplating the stations of the cross. Senn notes the pastoral concern to see the laity connected with the Gospel (Senn 1997, 238). In the end, it was the repetitive, liturgical use of Christian devotions which accomplished this.