This present work may be described as history of the medieval Popes, with the history of the city of Rome, and its civilization, as a background, the author's desire being so to combine the two stories as to produce a true picture of what Rome was in the middle ages. Volume one will deal with the state of the Roman Empire at the end of the fourth century, the final struggle between Paganism and Christianity (AD 394), the rise of the Primacy of Peter, and the church's struggle with Arianism.