Augustine of Hippo

Augustine of Hippo (354–430) was a theologian, philosopher, and the bishop of Hippo Regius in Numidia. After a journey through Manichaeism and Neoplatonism, he converted to Christianity in 386 under the influence of St. Ambrose and his mother Monica. His voluminous writings, including The City of God, On Christian Doctrine, and Confessions, profoundly shaped Western Christianity and philosophy. He is a Doctor of the Church and a foundational figure in the development of doctrines on grace, original sin, and the Trinity.