Which of the following accurately describes St. Augustine of Hippo's background?

St. Augustine of Hippo's background is notably marked by his conversion, which was significantly influenced by St. Ambrose, the Bishop of Milan. Augustine was initially a Manichean and led a life that included moral struggles and conflicts with sin, which he later detailed in his writings. His encounter with St. Ambrose was pivotal; through Ambrose's teachings and sermons, Augustine experienced a profound spiritual awakening that ultimately led to his conversion to Christianity. This transformation is famously recounted in his autobiographical work, "Confessions."

The other choices do not accurately reflect Augustine's background. He was not a monk and had a life marked by various sins before his conversion. Augustine authored many theological texts, including "The City of God" and "On Christian Doctrine," rather than just one book. Additionally, he became the Bishop of Hippo, which directly contradicts the notion that he was never a bishop. Understanding these aspects of Augustine's life is crucial to appreciating his theological contributions and the context of his writings.