- Dates: 354-430 AD
- Born to a Christian mother, Monica
- Tried various philosophies (Manichaeism), lived a sensual life.
- hears Ambrose preach, and begins to reconsider Christian faith not to be for uneducated idiots.
- Reads Life of Antony, and is converted as he is reading Scripture
- Becomes a priest, and then Bishop of Hippo.
_ Battles the Donatists: Donatists were rigorists, holding that the church must be a church of saints, not sinners, and that sacraments, such as baptism, administered by traditores (traitors: Christians who surrendered the Scriptures to the authorities who outlawed possession of them) were invalid. Probably in 311, a new bishop of Carthage was consecrated by someone who had allegedly been a traditor; his opponents consecrated a short-lived rival, who was succeeded by Donatus, after whom the schism was named. In 313, a commission appointed by Pope Militades found against the Donatists, but they continued to exist, viewing themselves, and not what was known as the Catholic Church, as the true Church, the only one with valid sacraments. Augustine's works against Donatists are: Against the Letter of Parmenian, 400; Baptism, Against the Donatists, 400-401; Against the Letters of Petilian, 401-405; The Unity of the Catholic Church, 405.
- Battles Pelagius. He engaged in debates with Pelagius and followers, who denied original sin and the necessity of God's grace for salvation, over how God saves people. He stressed the absolute depravity of man and the monergistic character of God's salvation