Augustine of Hippo, also known as Saint Augustine, was a theologian, philosopher, and the bishop of Hippo Regius in Numidia, Roman North Africa. Born as Aurelius Augustinus in Thagaste, Numidia, within the Roman Empire, Augustine's intellectual and spiritual journey has profoundly impacted the development of Western philosophy and Christianity.

Augustine's early life was marked by a period of spiritual restlessness and exploration. He initially embraced the Manichaean faith, only to later adopt the Hellenistic philosophy of Neoplatonism. However, it was his conversion to Christianity in 386, followed by his baptism, that set him on the path to becoming one of the most influential Church Fathers of the Latin Church during the Patristic Period. His works, including The City of God, On Christian Doctrine, and Confessions, continue to resonate with many.

After his conversion, Augustine developed a unique approach to philosophy and theology, integrating a variety of methods and perspectives. He believed in the indispensable grace of Christ for human freedom and made significant contributions to doctrines such as original sin and just war theory. As the Western Roman Empire began to disintegrate, he envisioned the Church as a spiritual City of God, distinct from the material Earthly City.

Augustine is venerated as a saint in the Catholic Church, the Eastern Orthodox Church, the Lutheran churches, and the Anglican Communion. He is recognized as a Doctor of the Church and the patron saint of brewers, printers, theologians, and several cities and dioceses. His thoughts profoundly influenced the medieval worldview, and he is considered one of the theological fathers of the Protestant Reformation, especially among Calvinists and Lutherans.

In the Eastern Christian tradition, Augustine's teachings have been more disputed, yet he has also influenced Eastern Church Fathers like Gregory Palamas. Despite controversies over doctrines such as the filioque, original sin, and predestination, Augustine's impact on Western Christian thought remains immense, rivaling that of Paul of Tarsus.