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.
Judaism
Over a long time, Jews formed distinct ethnic groups in several different geographic areas—amongst others, the Ashkenazi Jews (of central and Eastern Europe), the Sephardi Jews (of Spain, Portugal, and North Africa), the Beta Israel of Ethiopia, and the Yemenite Jews from the southern tip of the Arabian Peninsula. Many of these groups have developed differences in their prayers, traditions and accepted canons; however, these distinctions are mainly the result of their being formed at some cultural distance from normative (rabbinic) Judaism, rather than based on any doctrinal dispute.