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.
Reform Judaism
The next in size, by a wide margin, are the two British WUPJ-affiliates. In 2010, the Movement for Reform Judaism and Liberal Judaism respectively had 16,125 and 7,197 member households in 45 and 39 communities, or 19.4% and 8.7% of British Jews registered at a synagogue. Other member organizations are based in forty countries around the world. They include the Union progressiver Juden in Deutschland, which had some 4,500 members in 2010 and incorporates 25 congregations, one in Austria; the Nederlands Verbond voor Progressief Jodendom, with 3,500 affiliates in 10 communities; the 13 Liberal synagogues in France; the Israel Movement for Reform and Progressive Judaism (5,000 members in 2000, 35 communities); the Movement for Progressive Judaism (Движение прогрессивного Иудаизма) in the CIS and Baltic States, with 61 affiliates in Russia, Ukraine and Belarus and several thousands of regular constituents; and many other, smaller ones.