The Hasideans (Hebrew: חסידים הראשונים, Hasidim ha-Rishonim, Greek Ἀσιδαῖοι or Asidaioi, also transcribed as Hasidaeans and Assideans) were a Jewish group during the Maccabean Revolt that took place from around 167–142 BCE.
According to the book 1 Maccabees, during the early phases of the anti-Jewish decrees and persecution proclaimed by King Antiochus IV Epiphanes, some Hasideans joined up with Mattathias the Hasmonean as he martialed forces and allies for his rebellion (~167–166 BCE).
It appears to have been used as a loanword; the author of 2 Maccabees says the group was "called" Asidaioi, which is generally the terminology for introducing a non-Greek word to merely pronounce.
The author of 1 Maccabees, a source very much favorable to the Hasmonean family, then says this caused a group of Hasideans to join under Mattathias's revolt and provide needing backing.
So they trusted him; but he seized sixty of them and killed them in one day (...) Then the fear and dread of them fell on all the people, for they said, 'There is no truth or justice in them, for they have violated the agreement and the oath that they swore.'
This was in a later phase of the struggle, around 161 BCE, when the Seleucids had repealed the most onerous of the anti-Jewish decrees and were working to restore calm to the restive province.
But he [Alcimus] found an opportunity that furthered his mad purpose when he was invited by Demetrius to a meeting of the council and was asked about the attitude and intentions of the Jews.
He answered: 'Those of the Jews who are called Hasideans, whose leader is Judas Maccabeus, are keeping up war and stirring up sedition, and will not let the kingdom attain tranquility.
While it is possible that these books are describing a split among the Hasideans with some following Judas and others not, the favored explanation by scholars is that in 2 Maccabees, the term simply means "the faithful" in the sense of traditionalist Jews in general, and not a specific group.
The Hasideans had been true allies of Judas, but some of them had hoped to negotiate for concessions and relief thinking Alcimus a moderate, and the government used the opportunity to execute those who showed up.
In this view, the Hasideans were deeply religious but comparative "moderates" as their chief concern was the repeal of Antiochus IV's decrees forbidding Jewish practices.
This explains how Alcimus was able to lure some Hasideans to his side: by offering a return to the status quo ante and peace, when Judaism was accepted but the authority of the Seleucid government was unchallenged.
John J. Collins was disdainful of the hypothesizing done by other scholars; he wrote in 1977 that the Hasideans "had grown in recent scholarship from an extremely poorly attested entity to the great Jewish alternative to the Maccabees at the time of the revolt.
The historian Josephus describes three groups active in Hasmonean politics by 100 BCE: the mainstream and Hasmonean-skeptical Pharisees, the Hasmonean-supporting and influential among the upper classes Sadducees, and the outright anti-Hasmonean Essenes.
Heinrich Grätz supposes that after the Maccabean victories, the Hasideans retired into obscurity, being dissatisfied with Judas Maccabeus, and eventually became the order of the Essenes.
It appears to suggest more of a passive resistance and praises martyrdom; thus, the most important thing for the faithful was to remain 'pure' in their Judaism to maintain God's favor.
[16][20] Others are skeptical of the claimed connection; if the passage in 1 Maccabees 2 about the Hasideans being "mighty warriors" is accurate, that would not appear to align with Daniel's ideology.