Origins of Judaism
For centuries, the traditional understanding has been that Judaism came before Christianity and that Christianity separated from Judaism some time after the destruction of the Second Temple in 70 CE. Starting in the latter half of the 20th century, some scholars have begun to argue that the historical picture is quite a bit more complicated than that. In the 1st century, many Jewish sects existed in competition with each other, see Second Temple Judaism. The sects which eventually became Rabbinic Judaism and Early Christianity were but two of these. Some scholars have begun to propose a model which envisions a twin birth of Christianity and Judaism rather than a separation of the former from the latter. For example, Robert Goldenberg (2002) asserts that it is increasingly accepted among scholars that "at the end of the 1st century CE there were not yet two separate religions called "Judaism" and "Christianity"".
Daniel Boyarin (2002) proposes a revised understanding of the interactions between nascent Christianity and nascent Rabbinical Judaism in Late Antiquity which views the two religions as intensely and complexly intertwined throughout this period.
Judaism
The Jewish Enlightenment of the late 18th century resulted in the division of Ashkenazi (Western) Jewry into religious movements or denominations, especially in North America and Anglophone countries. The main denominations today outside Israel (where the situation is rather different) are Orthodox, Conservative, and Reform.While traditions and customs (see also "Sephardic law and customs") vary between discrete communities, it can be said that Sephardi and Mizrahi Jewish communities do not generally adhere to the "movement" framework popular in and among Ashkenazi Jewry. Historically, Sephardi and Mizrahi communities have eschewed denominations in favour of a "big tent" approach. This is particularly the case in contemporary Israel, which is home to the largest communities of Sephardi and Mizrahi Jews in the world. (However, individual Sephardi and Mizrahi Jews may be members of or attend synagogues that do adhere to one Ashkenazi-inflected movement or another.)