Book excerpt: Between the deaths of the Emperors Julian (363) and Justinian (565), the Roman Empire underwent momentous changes. Most obviously, control of the west was lost to barbarian groups during the fifth century, and although parts were recovered by Justinian, the empire's centre of gravity shifted irrevocably to the east, with its focal point now the city of Constantinople. Equally important was the increasing dominance of Christianity not only in religious life, but also in politics, society and culture. Doug Lee charts these and other significant developments which contributed to the transformation of ancient Rome and its empire into Byzantium and the early medieval west. By emphasising the resilience of the east during late antiquity and the continuing vitality of urban life and the economy, this volume offers an alternative perspective to the traditional paradigm of decline and fall.