The City of God by St. Augustine

St. Augustine's City of God is an enormous swath of late antique prose that as important as it is, not many of us actually invest the time to go all the way through. We have learned that by the end of his life Augustine had become an intellectual attack dog and system builder all at once. He bent on dismantling all history and culture that was non-Christian in nature; cementing more nebulous parts of Christian ethics into a fully codified whole.