Saint Augustine rose to sainthood in the Roman Catholic Church from very unpromising beginnings. He was born in North Africa under the Roman Empire to a pagan father and a Christian mother. Augustine was not a follower of Catholicism until his conversion later in his adult life. Instead, he joined a sect called the Manichees, which the Catholics considered heretical, and lived for a while in Rome. Augustine was academically gifted and worked as a teacher of rhetoric. His preconversion lifestyle was notorious; he had a mistress and many illegitimate children, to the despair of his devout mother. After a period of spiritual crisis—as detailed in his autobiographical work Confessions—he converted to Roman Catholicism in 387 AD and became a champion of the church. He became Bishop of Hippo (now in present-day Algeria) in 396 AD and helped to solidify Catholic doctrine and authority through his theological works including On Christian Doctrine (397 AD).

While Augustine does not speak much about his personal life or past in On Christian Doctrine, his personality nevertheless looms large in the work. He uses a direct and vigorous authorial voice and does not shy away from mocking his critics or openly voicing his objections to certain ideas (see “Literary Devices”).