St. Aurelius Augustine of Hippo (354-430) was a Manichean for 10 years before converted to Christianity in 386 ad. He would go on to become the best known Christian philosopher prior to the Middle ages.

He is best known to us for the first truly psychological, introspective account of his search for truth, in his Confessions. A hint of the intimate detail of his account can be gotten from one of his best known quotes: He prayed to God to "give me chastity and continence, but not yet!"

His philosophy is a loose adaptation of Plato to the requirements of Christianity. In order to reconcile the idea that God is good with the evil that obviously exists in the world, he turned to the concept of free will and our personal responsibility for sin. And he emphasized intentions over actions when it comes to assigning moral responsibility

There are, of course, problems with his arguments: If God is omniscient and omnipotent, he knows what we will do and in fact made us this way, so isn’t he still responsible for evil? Besides which, despite the admittedly great evil we human beings do to each other, aren’t there also natural disasters and diseases that could be considered evil, yet have nothing to do with our free will? These arguments would trouble philosophers even into the twentieth century. (See Dostoevsky’s The Brothers Karamazov for examples!)

Augustine became bishop of Hippo Regius (west of Carthage) in 395. He died in 430, during the siege of Hippo by the Vandals, a Germanic tribe that conquered North Africa (which was the “breadbasket” of Italy in those times!). You could say he lived through the fall of the Roman Empire.