Post-Nicene · 354 – 430
St. Augustine of Hippo
Thagaste / Hippo, North Africa
Biography
Augustine, after a restless youth chronicled in his Confessions, was converted and baptized by St. Ambrose in Milan in 387 and returned to Africa, becoming Bishop of Hippo in 396. He became the most influential theologian of the Latin West, combating the Manichaean, Donatist, and Pelagian heresies while writing on grace, the sacraments, and the two cities of God and man. He died as the Vandals besieged Hippo, having shaped Western Christian thought more than perhaps any other Father.
Historical background
Confronting the Donatist schism in North Africa, which held that sacraments administered by unworthy ministers were invalid, Augustine argued that the sacraments' validity depends on Christ acting through the minister, not on the minister's personal holiness, a doctrine later formalized as ex opere operato.
Major writings
Confessions
An autobiographical prayer recounting his conversion.
The City of God
A monumental defense of Christianity against pagan charges after the fall of Rome.
On Baptism, Against the Donatists
Defends the objective validity of sacraments regardless of the minister's worthiness.
Important teachings
Augustine teaches that Rome's judgment settles doctrinal controversy — 'Rome has spoken, the case is closed' — and that sacraments are valid by the power of Christ, not the minister's holiness. He also develops the classic Catholic doctrine of grace as both necessary and freely given, without denying human free will.
Quotations
“Rome has spoken; the case is concluded.”
“Believe, and you have eaten... he who believes in Him eats the living bread.”
“You have made us for Yourself, O Lord, and our heart is restless until it rests in You.”
“I should not believe the Gospel, except moved by the authority of the Catholic Church.”