Abstract: This book provides a detailed narrative history of the first six centuries of the Christian Church, from the first followers of Jesus to the papacy of Gregory the Great (590–604). It describes how Christianity, initially a persecuted sect, developed the ideas and organization to fulfil its ambition of being a universal faith, not tied to any particular people. The new religion had to separate itself completely from Judaism and set about the capture of the society and state of the Roman Empire during the centuries when the Empire divided into a Latin west and a Greek east and was beset by invasions by Christian and pagan barbarians, resulting in the disintegration of the western empire. Debates within Christianity, most fundamentally about the divine or human nature of Christ, are discussed in detail and in relation to both the politics and power struggles of the Empire and to the all-important question of authority within the Church. The origins and fate of schismatic movements are considered in the context of the struggle for authority among the rival sees of Rome, Constantinople, Alexandria, and Antioch. Christianity is discussed, therefore, in relation to its internal growth and divisions and also to how it was viewed by Jews and pagans, showing its debts to and division from both its Jewish origins and Graeco-Roman philosophy. The major theological and ecclesiastical texts and debates are considered in relation to the diverse beliefs and practices of the people who attended churches and the local and regional conditions that profoundly affected the outcome of events. The major Christian thinkers and their contributions to the success of Christianity are examined in detail. The importance of theological, personal, and political factors is demonstrated in showing how they fostered divisions in the Church and prevented reconciliation and balanced against the desire of successive emperors to foster unity for political reasons. The Church captured society, east and west, but at the cost of long-lasting divisions and conflicts.

Keywords: Christian Church, Christian theology, Church fathers, Eastern Church, papacy, Roman Empire