who is considered the most important person in the early spread of christianity
Christianity in the 5th century Saint Augustine, Bishop of Hippo Regius, was a philosopher and theologian. Augustine is one of the most important figures in the development of Western Christianity. Augustine was radically influenced by Platonism.[18] He framed the concepts of original sin and just war as they are understood in the West. When Rome fell and the faith of many Christians was shaken, Augustine developed the concept of the Church as a spiritual City of God, distinct from the material City of Man.[19] Augustine's work defined the start of the medieval worldview, an outlook that was later firmly established by Pope Gregory the Great.[19]