Jungmann, Josef A., S.J. "Chapter Twenty-Two: The Daily Office." The Early Liturgy to the Time of Gregory the Great. (translated by Francis A. Brunner, C.S.S. R., Notre Dame, Indiana: University of Notre Dame Press, 1959, pp. 278-287.
Jungmann asks, based on the centuries of liturgical development, what Christian worship actually looked like by the end of antiquity (Jungmann 1959, 278). It is clear to Jungmann that Sunday was the day of the divine service for the community. In general, each church had one Sunday service, and the Mass would occur. However, Jungmann does not think communion (the Mass) was celebrated on days other than Sundays except on special occasions (Jungmann 1959, 279). There may well have been additional, more private services celebrated in chapels within the churches. There is evidence of settings of the Mass for different purposes.
In public, however, Jungmann finds the development of the canonical hours (Jungmann 1959, 280). Particularly a Matins and Vespers seem to have been commonly used in public worship on the days other than Sunday. This is clear from, among other sources, the developed nature of the canonical hours described in the Rule of St. Benedict (Jungmann 1959, 282).
Jungmann reviews the specific arrangements of the different offices (Jungmann 1959, 283). They centered specifically around the Scripture readings, a practice which grew from the concept of God speaking to his people by his grace (Jungmann 1959, 284). The essential outline of the liturgy has changed little over the centuries.