Final answer:
St. Augustine of Hippo was the influential Saintly Bishop in Augustine's life, known for his theological contributions and combating the Donatist controversy.
Step-by-step explanation:
The Saintly Bishop influential in Augustine's life was none other than St. Augustine of Hippo himself. As the Bishop of Hippo, Augustine was instrumental in the religious and philosophical development of Christianity, taking strong positions against heresies of his time. His writings, particularly The City of God and Confessions, have left a lasting impact on Christian theology and the understanding of philosophical issues like the nature of time and free will.
Augustine fought against the Donatist controversy as the chief opponent at the 411 Council of Carthage, resulting in the expulsion of the Donatists from the church. His theological works sought to defend Christian orthodoxy and articulate doctrines that would shape European philosophy for centuries. Moreover, through his efforts and teachings, Augustine worked to reconcile Christian beliefs with the intellectual tradition of the classical world during a time of significant political and social transition as the Roman Empire faced decline.