This dissertation examines Byzantine relief icons from the ninth to the fifteenth century, challenging the prevailing scholarly emphasis on panel-painted sacred images. While Byzantine icons are often equated with painting, the material record reveals a rich corpus of relief imagery fashioned from marble, ivory, gems, wood, and precious metals. Much like their painted counterparts, these sculptural icons played a prominent role both in public and private spaces, offering an alternative lens through which to examine Byzantine conceptualizations and perceptions of the sacred image. Through a close analysis of their execution, this thesis argues that the inherent plasticity of relief icons engaged worshippers both visually and haptically. In some instances, traces of tactile use invite a reconsideration of icons not as static objects but as dynamic entities whose meaning evolved through pious touch and interaction. Theological writings, hagiographies, and poetry provide valuable insight into how the physical qualities of these icons were perceived, as well as the bodily and affective disposition of viewers in prayer before them. Notably, pious desire and physical stillness emerge in these accounts as significant dimensions of prayer and devotion. Moreover, by integrating perspectives from phenomenology, anthropology, and material studies, this thesis demonstrates that relief imagery provoked reflections on crucial theological dimensions such as mimesis and the absent-present nature of the icon. By providing beholders with a corporeal experience of these concepts, relief icons reinforced the belief that sensory perception was integral to apprehending spiritual ideas. While relief icons have long been marginal in scholarly inquiry, this dissertation repositions them at the heart of Byzantine religious experience. It moves beyond the notion that Byzantium rejected sculpture due to fears of idolatry and associations with “pagan” statuary. Instead, this study demonstrates that the plastic form was not only accepted but actively central to Byzantine devotional life.