How do liturgies fashion and communicate theology? With the Ecclesiastic Rite of Constantinople-once celebrated not only in the city's Great Church (Hagia Sophia) but in churches throughout the Byzantine world-as evidence, this study demonstrates that hymnography offers one avenue by which to approach this question and, thus, one of the most important points of direct access to liturgical theology. The volume presents, firstly, a comparative edition of the corpus of Greek hymns found in the oldest witnesses to this Middle Byzantine "cathedral" or "asmatic" patriarchal liturgical tradition, together with an English translation. It situates the hymns in their historical and liturgical contexts and reassesses the relationship between the earliest manuscript sources. Secondly, it offers a commentary on twenty exemplary troparia for the highest feasts of the liturgical year, setting them within a heortological, ritual, and literary frame of reference. The systematic analysis of the living hymn texts shows that they are part of an ancient Christian textual world fundamentally characterised by diverse receptions of biblical texts and themes. This work closes a gap in research in historical and theological liturgical studies and Byzantine literary history, renders accessible an important but hitherto neglected corpus of Greek Christian hymns, and lays the textual ground for numerous future studies.