Christianity, initially emerging as a Jewish sect, progressively separated from its Jewish origins through a confluence of theological, social, and political factors. Early Christian thinkers, such as Justin Martyr, were pivotal in this divergence. Justin Martyr advanced the concept of supersessionism, asserting that the New Covenant in Christ superseded the Old, and he reinterpreted Jewish scriptures to highlight their fulfillment in Jesus. He championed Christianity as a universal faith, distinct from the perceived particularism of Judaism, emphasizing unique Christian practices like baptism and beliefs such as Christ's divinity.
The Council of Nicaea then solidified core Christian doctrines, establishing a unique theological framework and contributing to the marginalization of Jewish communities. Later, Augustine of Hippo’s influential doctrines, including original sin and predestination, further elaborated a distinct Christian theological universe. His controversial interpretation of "compel them to come in" from the Parable of the Great Banquet, was used to justify religious coercion, marked a definitive and often hostile separation.
Key historical events further propelled this separation. The destruction of the Second Temple and the Bar Kokhba Revolt led Christians to distance themselves from Jewish nationalistic movements. The formal exclusion of those who believed in Jesus as the Messiah from mainstream Jewish community life in synagogues solidified Christianity’s identity as a distinct religion.

The Theological History of the Parting of the Jewish & Christian Ways (50 CE – 400 CE)
The Archeology of Alterity: The Path Towards Ecclesiastical Separation of Christianity From Judaism
Timeline For Christianity’s Split From Judaism
1. Architects of the Divide: How Early Theologians Separated Christianity from Judaism
2. Ignatius of Antioch: Forging Christian Identity In The Crucible Of Faith
3. Justin Martyr: The Philosopher Who Defined Christianity's Break From Judaism
4. Justin Martyr: Formulating Christianity's Identity From Its Jewish Roots