Saint Augustine

North African bishop and theologian — author of Confessions and The City of God — who created the Christian theological framework for original sin, predestination, grace, and just war — whose thought shaped Western Christianity more than any other figure after Paul.

Creates the Western Christian theological framework — Augustine's synthesis of Neoplatonism and Christian theology in the Confessions and City of God established the intellectual framework through which the Christian West understood sin, grace, the Church, and history; his concept of original sin and divine grace structured the Protestant Reformation a thousand years later.