The Interior Life, and the Invention of a Genre

Augustine wrote his other great work, The City of God, in direct response to a historical shock: the sack of Rome by Alaric's Visigoths in 410, an event that let pagan critics argue Rome's abandonment of its old gods for Christianity had brought divine punishment. Augustine's answer, composed over more than a decade, reframes history itself around two intermingled cities, the earthly city bound to temporal power and self-love, and the City of God bound to eternal truth and love of God, arguing that Rome's fate was never the real measure of Christian hope in the first place. The work became a foundational text for later Christian political theology, read for centuries as authority on the proper relationship between church and state.

Augustine also fought a long theological battle against the British monk Pelagius, who taught that humans could achieve moral perfection and salvation through their own effort and free will alone, without dependence on divine grace. Augustine's opposing doctrine, that grace is necessary and prior to any good human act because original sin has left the will itself damaged, was affirmed by church councils and shaped mainstream Western Christian theology, including the later Reformation's own arguments about grace, far more decisively than Pelagius's position, which was condemned as heresy. Augustine died in 430 as Hippo itself lay under siege by the Vandals, the Roman world he had defended in writing collapsing around him in fact.