This comprehensive study explores the profound religious shift that reshaped the Roman Empire between the third and seventh centuries CE. Tracing the gradual decline of traditional Roman polytheism and the concurrent rise of Christianity, the book examines the political, social, and cultural forces that drove this transformation. Through detailed analysis of imperial policies, intellectual debates, ritual practices, and popular beliefs, Philip Davies reveals how the once-dominant pagan religion adapted, resisted, and ultimately gave way to a Christianized imperial order. Drawing on primary sources, archaeological evidence, and modern scholarship, the work highlights the complex interplay of syncretism, persecution, accommodation, and innovation that characterized this pivotal era. Offering fresh insights into the shifting notions of sacred space, family religion, and communal identity, the book illuminates the legacy of Late Antiquity's religious metamorphosis and its enduring impact on Western civilization.