Judaism
Around the 1st century CE, there were several small Jewish sects: the Pharisees, Sadducees, Zealots, Essenes, and Christians. After the destruction of the Second Temple in 70 CE, these sects vanished. Christianity survived, but by breaking with Judaism and becoming a separate religion; the Pharisees survived but in the form of Rabbinic Judaism (today, known simply as "Judaism"). The Sadducees rejected the divine inspiration of the Prophets and the Writings, relying only on the Torah as divinely inspired. Consequently, a number of other core tenets of the Pharisees' belief system (which became the basis for modern Judaism), were also dismissed by the Sadducees. (The Samaritans practiced a similar religion, which is traditionally considered separate from Judaism.)
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).