The activity of the Zealots and Sicarii further destabilized the political situation. The name Sicarii comes from a short sword that could be concealed under clothing. The Sicarri would mingle into a crowd and assassinate their enemies. They were not really a religious sect, but rather a group of nationalist who advocated revolt against the Romans. They were “urban assassins,” primarily attacking the Jewish aristocracy who were pro-Roman. Eventually they took to burning estates and taking hostages. Jonathan the High Priest was their first victim. [Note that the word is used in Acts 21:38 to describe the activities of “The Egyptian,” the NIV translates the word as “terrorist” to avoid confusion with the later sicarri movement.]
Josephus, JW 2.13.3 (cf. Ant 20.8.10) (254) When the country was purged of these, there sprang up another sort of robbers in Jerusalem, which were called Sicarii, who slew men in the daytime, and in the midst of the city; (255) this they did chiefly at the festivals, when they mingled themselves among the multitude, and concealed daggers under their garments, with which they stabbed those that were their enemies; and when any fell down dead, the murderers became a part of those that had indignation against them; by which means they appeared persons of such reputation, that they could by no means be discovered. (256) The first man who was slain by them was Jonathan the high priest, after whose death many were slain every day, while the fear men were in of being so served, was more afflicting than the calamity itself; (257) and while everybody expected death every hour, as men do in war, so men were obliged to look before them, and to take notice of their enemies at a great distance; nor, if their friends were coming to them, durst they trust them any longer; but, in the midst of their suspicions and guarding of themselves, they were slain. Such was the celebrity of the plotters against them, and so cunning was their contrivance.
Their terrorist activities helped to bring on the revolution. The random assassinations lead to a distrust among the aristocracy and a general fear from the ruling class, leading to a breakdown of social order.

A possible New Testament reference is the disciple of Jesus, Simon the Zealot. Is this disciple a political zealot, a revolutionary? Most New Testament scholars think not, preferring to take the word “zealot” in this context as spiritual zeal. Personally, I wonder about the word “zeal” having a modern sense of “spirituality” in the context of A.D. 30 Galilee, where only twenty years beforehand Judas led a revolt against Rome which might be described as “zeal.” Notice also, there are two men named Judas out of the twelve disciples. Judas was a patriotic name going back to Judas Maccabees, the last successful Jewish rebel against foreign power. It is possible these men were born during the activities of Judas the Galilean.
The Jewish Christians living in Jerusalem were therefore in a dangerous place. If they appeared to be too open to Paul’s Gentile churches they ran the risk of real persecution from these more radical elements, yet they clearly preached Jesus was the Messiah, that he was crucified and raised from the dead, and that he was coming back soon to render judgment (on the temple officials, the Romans, etc.) and re-establish Messianic Kingdom expected by the prophets.
Theudas is a common name in first century inscriptions. In addition, the period after the death of Herod the Great saw many rebellions, so it is likely that Gamaliel refers to a leader of one of these earlier rebellions. Judas the Galilean lead a tax-revolt about A.D. 6, described by Josephus (Antiq 18.1.6, §23). Like Thuds’, he died and his followers dispersed.
Social bandits portray themselves as robbing the rich and giving to the poor, “righting wrongs” and other social evils, and providing justice for the oppressed lower classes. This is something like Robin Hood, or the American “gangster” of the depression era (Pretty Boy Floyd, Jesse James, etc.) The social banditry described by Josephus took place during the reign of Herod the Great, but it continued throughout the period of the New Testament, culminating on the rebellion against Rome in A.D. 66.