Byzantium: The Early Centuries:Volume 1 by John Julius. Norwich
This is the story of the Byzantine Empire, from its earliest days to the beginnings of the emergence of its only European rival, the Holy Roman Empire. Those first five centuries saw the adoption of Christianity by the Graeco-Roman world, the fall of Rome and the reigns of Constantine and Justinian. They were centuries of bloodshed and controversy, in which the Empire struggled for its life against enemy armies, and in which its citizens argued passionately about the true nature of Christ and his Church. Above all they were centuries of scholarship and creativity, in which the knowledge of the ancient world was kept alive, and in which the Byzantine genius brought about a flowering of art and architecture. John Julius Norwich is the author of many books including two on the history of the Normans in Sicily, and A History of Venice, and he has written and produced some 30 historical documentaries for television.