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.
Hasideans
Scholars have until recently started with the assumption that Hellenism "took root only in the upper classes of society, the main body of the [Jewish] nation being wholly untouched by it" and distinguished between the pious, law-abiding majority of the people and the Hasideans as a society of "extra-pious" Jews. However, the sources mentioned do not justify such a view. The συναγωγ σιδαίων of the books of the Maccabees, upon which so much emphasis is laid, corresponds, as has already long been known, to the קהל חסידים of the Psalms, which means neither "sect" nor "society", but only "congregation", with no idea of party. The piety attributed to Ḥasidim in the Talmudic sources is not in any way suggestive of a sect (Lehmann, in "R. E. J." xxx. 182 et seq.). The supposition that they were a sect closely associated with the scribes, and related to them, rests only on the fact that the two classes are mentioned together in I Macc. vii. 12, 13; the genuineness of verse 13, however, has been questioned by Hitzig ("Gesch. des Volkes Israel," p. 417).