<P> The history of early Christianity covers the period from its origins to the First Council of Nicaea in 325 . </P> <P> The first part of the period, during the lifetimes of the Twelve Apostles, is traditionally believed to have been initiated by the Great Commission of Jesus (though some scholars dispute the historicity of this event), and is called the Apostolic Age . The earliest followers of Jesus comprised an apocalyptic, Second Temple Jewish sect, which historians refer to as Jewish Christianity . Though Paul's influence on Christian thinking is said to be more significant than that of any other New Testament author, the relationship of Paul of Tarsus and Judaism remains a matter of dispute . Early Christianity gradually grew apart from Judaism during the first two centuries of the Christian Era; it established itself as a predominantly gentile religion in the Roman Empire . </P> <P> In the Ante - Nicene Period (literally before the First Council of Nicaea in 325), following the Apostolic Age, both incredible diversity and unifying characteristics lacking in the apostolic period emerged simultaneously . Part of the unifying trend was an increasingly harsh rejection of Judaism and of Jewish practices . By the beginning of the Nicene period, the Christian faith had spread throughout Western Europe and the Mediterranean Basin, and to North Africa and the East: see Early centers of Christianity . The Mediterranean Christianity journey consisted of 48 cities that St John visited to get the gentiles to join the Christian community . </P> <P> Historians commonly use the First Council of Nicaea in 325 and the toleration / promotion of Christianity by Emperor Constantine I (reigned 306--337) in the Roman Empire to mark the end of early Christianity and the beginning of the era of the first seven Ecumenical Councils (325--787). </P>

Where was christianity most strongly established by ad 325