The most universal and comprehensive example of this was Augustine’s _City of God_, already adverted to. Its subject was the ways of God with men. It embraced history, philosophy, and religion. It was the final Christian apology, and the conclusive proof of Christian doctrine, _adversum paganos_. To this end Augustine unites the manifold topics which he discusses; and to this end his apparent digressions eventually return, bearing their sheaves of corroborative evidence. In no province of inquiry does his apologetic purpose appear with clearer power than in his treatment of history, profane and sacred.[84] Through the centuries the currents of divine purpose are seen to draw into their dual course the otherwise pointless eddyings of human affairs. Beneath the Providence of God, a revolving succession of kingdoms fill out the destinies of the earthly Commonwealth of war and rapine, until the red torrents are pressed together into the terrestrial greatness of imperial Rome. No power of heathen gods effected this result, nor all the falsities of pagan philosophy: but the will of the one true Christian God. The fortunes of the heavenly City are traced through the prefigurative stories of antediluvian and patriarchal times, and then on through the prophetic history of the chosen people, until the end of prophecy appears--Christ and the Catholic Church. The _Civitas Dei_ is the crowning example of the drastic power with which the Church Fathers conformed the data of human understanding into a substantiation of Catholic Christianity.[85] At the time of its composition, the Faith needed advocacy in the world. Alaric entered Rome in 410; and it was to meet the cry of those who would lay that catastrophe at the Church’s doors that Augustine began the _Civitas Dei_. Soon after, an ardent young Spaniard named Orosius came on pilgrimage to the great doctor at Hippo, and finding favour in his eyes, was asked to write a profane history proving the abundance of calamities which had afflicted mankind before the time of Christ. So Orosius devoted some years (417-418) to the compilation of a universal chronicle, using Latin sources, and calling his work _Seven Books of Histories “adversum paganos.”_[86] Addressing Augustine in his prologue, he says: