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.
Hasidic Judaism
In 2016, a study conducted by Prof. Marcin Wodziński, drawing from the courts' own internal phone-books and other resources, located 129,213 Hasidic households worldwide, about 5% of the estimated total Jewish population. Of those, 62,000 resided in Israel and 53,500 in the United States, 5,500 in Britain and 3,400 in Canada. In Israel, the largest Hasidic concentrations are in the Ultra-Orthodox neighbourhoods of Jerusalem – including Ramot Alon, Batei Ungarin et cetera – in the cities of Bnei Brak and El'ad, and in the West Bank settlements of Modi'in Illit and Beitar Illit. There is considerable presence in other specifically Orthodox municipalities or enclaves, like Kiryat Sanz, Netanya. In the United States, most Hasidim reside in New York, though there are small communities across the entire country. In Brooklyn, Borough Park, Williamsburg, and Crown Heights all house a particularly large population. So does the hamlet of Monsey in upstate New York. In the same region, New Square and Kiryas Joel are rapidly growing all-Hasidic enclaves, one founded by the Skver dynasty and the other by Satmar. In Britain, Stamford Hill is home to the largest Hasidic community in the country, and there are others in London and Prestwich in Manchester. In Canada, Kiryas Tosh is a settlement populated entirely by Tosh Hasidim, and there are more adherents of other sects in and around Montreal.