This is a study of the physical manifestation of the cult of the Virgin Mary in Late Antique Egypt, that is, of the point at which Marian veneration, which scholars generally agree coalesced in the fifth century, spilled over into the physical sphere. Three diverging source materials (papyri/inscriptions, archaeology and iconography) are explored in order to answer the central question, which asks: to what extent does the evidence for the physical materialization of the cult of Mary reflect its geographical and chronological diffusion in Late Antique Egypt? Each of the sources materials are collected and analyzed in an independent chapter. The study begins with the papyrological/epigraphical evidence, as it represents the largest body of materials and offers the most substantial datable evidence. Although the papyri and inscriptions are not themselves tangible manifestations of the cult of Mary, they nevertheless mention at least 23 churches or monasteries that were dedicated to her. In Chapter 2, the extant archaeological evidence supplements the data collected in the textual materials by providing an analysis of the layout and iconographical programmes of the few churches of Mary that are actually preserved. Chapter 3 collects 43 wall paintings that depict Mary and analyzes their varying iconographic patterns and immediate spatial contexts. The individual source materials are then brought together for a broader geographical and chronological investigation, which demonstrates that despite the assumed presence of a cult of Mary by the fifth century, this was only the starting point for the consolidation and diffusion of her cult, which reached its peak in the sixth and, especially, the seventh century. This study is the first synthesis of the physical output of the cult of Mary in Late Antique Egypt and thus advances our knowledge of her integration into the society of Christian Egypt on both the chronological and topographical axes. As such, it is also of importance to studies of her cult elsewhere in the Late Antique world, where sources may not be as plentiful and varied.