From the Globe and Mail:

The Zealots, who according to many histories made up the community who succumbed to the Roman siege of Masada, were a revolutionary Jewish sect that advocated a theocracy. Noted for their fierce opposition to Roman rule, the Zealots were hostile even to Jews who sought reconciliation with pagan and polytheistic Rome.

Extremists among the group practised terrorism and assassination to defend their beliefs, and became known as Sicarii, or "dagger men."

Lurking in public places, they waited to assault people, whether Romans or Jews, they viewed as friendly to Rome.

In AD 6, when the Romans ordered a census of Galilee, the Zealots rallied the residents to non-compliance on the grounds that to co-operate would be to acknowledge the right of pagans to rule their nation.

The incident became the impetus for an insurrectionist movement that at first involved only scattered acts of revolt, but ultimately expanded and took a military form, finally instigating the First Jewish Revolt.

The heroism and sacrifice of the Jews at Masada is emphasized in standard Israeli texts on the subject, but some believe the story has been sanitized for popular consumption.

In his book The Masada Myth, Israeli sociologist Nachman Ben-Yehuda writes that it was the Sicarii who were cornered on the Masada.

"The Sicarii were disliked and were driven out of Jerusalem not by Romans but by other Jews a long time before, . . ." he wrote.

"Thus the group on top of Masada was a group of assassins, not Zealots. During their stay on Masada, the Sicarii raided nearby (Jewish) villages, killed the inhabitants and took their food. . . ."