This dissertation is about the ninth-century Byzantine nun Kassia who is perhaps the most famous hymnographer of her time. Reconstructions of her character and work have largely been done in specialized categories, thus leading to many isolated and idiosyncratic readings. In contrast, this dissertation shall use a mosaic methodology, examining the various historical and theological developments leading up to ninth-century Byzantium, and thus giving a more developed context in which to examine Kassia. This new approach will allow for a stronger and more multi-layered reconstruction of the only female hymnographer whose work has made it into the liturgical life of the Byzantine church. The historical reconstruction of ninth-century Byzantium will detail the social, political, economical, educational, and cultural milieus that all intersected and interpenetrated one another in discourse. In particular, it shall focus upon the figure Theodore the Studite and his monastery of Stoudion whose intellectual renaissance greatly affected the culture of ninth-century Byzantium. It shall also give an account of the iconoclastic controversy that shook the state at its devotional and political core. Alongside the above, this study will detail the theology that underpins liturgical-musical development, thus creating an amalgam that could aptly be called ‘theomusicology.’ This idea has largely been ignored when examining Kassia and will provide a new avenue of historical reconstruction. Utilizing these various frames, this dissertation shall undertake an exegesis of Kassia’s liturgical and non-liturgical works, showing how they influenced both the construction and content of her writings. In particular, it shall examine her gnomic verses and maxims, her work in the Menaia, or the book that outlines the weekly services for each month, and the Triodion, the liturgical book used by Byzantines for their religious season known as Lent. Her sticheron idiomelon, ‘The Fallen Woman,’ shall receive special attention, as it is her most known work. This study will then draw various conclusions based upon its findings, detailing a far more developed Kassia than has been done previously in other studies. By explaining her theomusicological thought along with historical influences, this study ultimately will show how Kassia used music as the vehicle to carry her thematic points, creating an ecstatic emotional experience in her hymns.