Augustine begins Book V by praising God and explaining the importance of owning up to the completeness and universality of the one true Christian God. He does this through a series of complicated scriptural references, and he asserts that the "unjust" will have no escape from God.
At 28, Augustine was living in Carthage teaching rhetoric. The "most learned" Bishop of the Manichaean religion, a man named Faustus, came to Carthage, and Augustine spoke to him. Faustus, whom Augustine calls "a great snare of the devil," was not able to complete Augustine's conversion to Manichaeism because Augustine found fault with the Bishop's logic and overall conception of religion. Augustine was gradually becoming aware that he was more educated and had a more critical mind than those around him. He "retained in his mind" the teachings of some philosophers, and Faustus' beliefs could not stand up to Augustine's logical attacks. He reflects that the astrological teachings of the Manichees, even when they accurately predicted heavenly events like eclipses, did not help him develop faith in God. He sought a truer and more spiritual path than the one Faustus taught.
Through information provided to him by his friends, Augustine learned that he could make more money teaching rhetoric in Rome than he could in Carthage. In despair over the Manichaean religion's inability to grab hold of his spiritual imagination, decided to flee to Rome. He lied to his mother about his departure in order to avoid an emotional scene. Even so, she lamented his leaving, and in hindsight Augustine regrets having told a falsehood to this "handmaid of the Lord."
Upon arriving in Rome, Augustine fell very ill with a fever. Though Monica did not know of Augustine's illness, she was praying for him back in Africa. Augustine credits Monica's prayers with his recovery. In Rome, Augustine spent some time listening to the teachings of the Academics, a school of Skeptic philosophers whose philosophical rigor led them to question the validity and internal logic of every religion and philosophical system of their day. While still nominally a Manichee, Augustine admired the Academics' strict methods of logical and critical analysis, and applied their teachings to his later writings.
While law and custom permitted the students in Carthage to run wild and commit various acts of vandalism - a lack of studious intent which annoyed Augustine to no end - Augustine was shocked to find an even more grievous practice of cheating teachers out of their fees in Rome. This upset Augustine greatly and he planned to take a professorship in Milan, which was then the seat of the Imperial Court. Though still a member of the Manichaean faith, he was questioning its validity more than ever before.
In Milan, Augustine had cause to listen to the great Catholic Bishop Ambrose, head of the Milan Church at the time. Ambrose gave sermons which Augustine found impressive from a literary and oratorical point of view. Furthermore, they introduced Augustine to the possibilities of an allegorical interpretation of the Bible. This, Augustine later learned, opens up many possibilities for the reconciling of Scripture with moral and doctrinal points. Augustine began to address some of his own issues with the Catholic faith - namely his vision of the material God and his Manichaean belief in the physicality of evil. Ambrose did not aggressively try to convert Augustine, but merely impressed him with his erudition and faith.
Monica joined Augustine in Milan and lived a simple and admirable life as a Christian widow. Patrick had died, and we learn that he converted to Christianity towards the end of his life. Through the influence of Bishop Ambrose and Monica, Augustine, though still uncertain about his faith, decided to become a catechumen.
The stranger aspects of the Manichaean faith - the assertion that evil is a physical being, and the ideas concerning astrology - began to chafe on Augustine's critical mind. He could not reconcile the faith with the principles of logic and critical inquiry - nor, however, coul