Judaism
Christianity was originally a sect of Second Temple Judaism, but the two religions diverged in the first century. The differences between Christianity and Judaism originally centered on whether Jesus was the Jewish Messiah but eventually became irreconcilable. Major differences between the two faiths include the nature of the Messiah, of atonement and sin, the status of God's commandments to Israel, and perhaps most significantly of the nature of God himself. Due to these differences, Judaism traditionally regards Christianity as Shituf or worship of the God of Israel which is not monotheistic. Christianity has traditionally regarded Judaism as obsolete with the invention of Christianity and Jews as a people replaced by the Church, though a Christian belief in dual-covenant theology emerged as a phenomenon following Christian reflection on how their theology influenced the Nazi Holocaust.
Split of Christianity and Judaism
Most historians agree that Jesus or his followers established a new Jewish sect, one that attracted both Jewish and gentile converts. According to New Testament scholar Bart D. Ehrman, a number of early Christianities existed in the first century CE, from which developed various Christian traditions and denominations, including proto-orthodoxy. According to theologian James D. G. Dunn, four types of early Christianity can be discerned: Jewish Christianity, Hellenistic Christianity, Apocalyptic Christianity, and early Catholicism.