Final answer:
Augustine, as he aged, eventually converted to Christianity and became a significant figure within the Church, particularly noted for his theological contributions in works like 'The City of God' and for his leadership against heresies such as Donatism.
Step-by-step explanation:
As Augustine aged, he became increasingly involved with and influenced by the Christian faith. During his studies in Carthage and his time in Milan, Augustine encountered Christian doctrines and after reading about Antony of the Desert, he ultimately converted to Christianity. Later, as Bishop of Hippo, Augustine played a crucial role in theological disputes, particularly against the Donatists and other heresies, affirming the importance of divine grace and the goodness of all creation by God.
Augustine's works, such as The City of God and his Confessions, deeply explored Christian doctrine, the nature of time, free will, and divine providence, leaving a lasting impact on Western philosophy and the Christian Church.