This volume explores the power of matter and materials in the Eastern Roman Empire, also known as Byzantium. Recent attention to matter as dynamic and meaningful constitutes an emerging, interdisciplinary field of inquiry known as materiality, new materialism, or the material turn. Materials can be symbolic, but matter can also act on human subjects. This volume builds on these insights to consider the role of matter, materials, form, and embodied experiences in Byzantium. In many respects, Byzantine materiality represents a continuation of its Greco-Roman inheritance, which was also shared by neighboring peoples such as the Umayyads and Abbasids. But the Byzantines also developed their own, unique perspectives on matter and form, as with their parsing of the sacred materialities of icons, the Eucharist, and relics. Chapters in this volume consider the cultural meanings and functions of materials such as gold and ivory, the materiality of icons and relics, experiences of objects, as well as Byzantine philosophies of matter and form. Materiality takes center stage in Byzantine constructions of power, luxury, belief, and identity, which will be of interest to scholars and students of Byzantium and the wider medieval world.