City of God is a foundational text supporting Christianity against other belief systems, specifically Roman paganism. It is a litigious, point by point breakdown as written by Saint Augustine, and is most definitely a masterwork. This text is built on historical works, mythological writings, and scripture. It gives us a picture of what life was like for Christians in the time that Rome was captured by King Alaric of the Visigoths.
This is my personal study, and involves a great deal of paraphrase. I highly recommend getting your own copy to read (available for free online), as I am incapable of fully encompassing the value of the work.
Modern Survival Arkansas 