In God's Country
The idea of Christendom, a domain where Christian politics and ecclesiology entwined, captivated the medieval imagination. Yet Augustine, whose thought (especially as expounded in his massive City of God) dominated the Middle Ages, never advocated such a system. Orosius, one of his students, did.
When Augustine began work on City of God, in 412, Rome was suffering under its first hostile occupation in centuries. Some disillusioned Roman citizens blamed Christians and their God, who seemed less able to defend the city than the old pagan gods had been. Augustine refutes this claim in City of God, especially the first five books.
The invasion of Rome drove many citizens to seek refuge in comparatively calm northern Africa, among them a young scholar named Orosius. Augustine welcomed him, describing him in a letter as a "young man … who is in the bond of the Catholic peace a brother, in the point of age a son, and in honor a fellow presbyter—a man of quick understanding, ready speech, and burning zeal, desiring to be in the Lord's house a vessel rendering useful service."
Orosius stayed with Augustine for about a year. Augustine was at the time busy working on City of God, combating the Pelagian heresy, and leading a large congregation. These duties left him no time to write a detailed, direct attack (beyond book three of City of God) on pagans and their nostalgia for a golden age before the rise of Christianity. So, according to Orosius, Augustine asked his protégé to mount the assault:
"You [Augustine] bade me, therefore, discover from all the available data of histories and annals whatever instances past ages have afforded of the burdens of war, the ravages of disease, the horrors of famine, of terrible earthquakes, extraordinary ...