St AugustineAu·gus·tine, St1 /ɔːˈɡʌstɪn $ ˈɔːɡəstiːn/ (also St Augustine of Hippo / $ ˌ.... ˈ../) (354–430 AD) a North African Christian leader, philosopher, and writer whose books, such as Confessions and The City of God, strongly influenced the development of Christianity