Sicarii comes from the Latin word for dagger sica, and means assasins or murderers. The Sicarii, or "dagger men" carried out murders and assassinations with short daggers.
The Sicarii were led by descendents of Judas of Galilee, who helped foster revolt against direct Roman rule in 6 CE, when they attempted to carry out a census of the Jews under the rule of Roman governor Quirinius in Syria, so that they could tax them. Judas famously proclaimed that the Jews should be ruled by God alone.
Jewish groups began violent resistance to Roman rule around 50 CE, when the Sicarii and other groups started using guerrilla or terrorist tactics. All out war between the Jews and the Romans broke out in 67, when Romans invaded. The war ended in 70 CE, when Roman forces devastated Jerusalem. Masada, Herod's famous fortress was conquered by siege in 74.
As political scientist and terrorist expert David C. Rapaport has pointed out, the Sicarii were distinct in primarily targeting other Jews considered to be either collaborators or quiescent in the face of Roman rule.
They attacked, in particular, Jewish notables and elites associated with the priesthood. This strategy distinguishes them from the Zealots, who aimed their violence against Romans.
These tactics were described by Josephus as beginning in the CE 50s:
… a different type of bandits sprang up in Jersualem, the so-called sicarii, who murdered men in broad daylight in the heart of the city. Especially during the festivals they would mingle with the crowd, carrying short daggers concealed under their clothing, with which they stabbed their enemies. Then when they fell, the murderers would join in the cries of indignation and, through this plausible behavior, avoided discovery. (Quoted in Richard A. Horsley, "The Sicarii: Ancient Jewish "Terrorists," The Journal of Religion, October 1979.)
The Sicarii operated primarily in the urban environment of Jerusalem, including within the Temple. However, they also committed attacks in villages, which they also raided for plunder and set on fire in order to create fear among Jews who acquiesced or collaborated with Roman rule. They also kidnapped notables or others as leverage for the release of their own members held prisoner.
The Sicarii and the Zealots
The Sicarii are frequently described as the same as or a subset of the Zealots, a political party who opposed Roman rule in Judea in the period just before Jesus' birth. The role of the Zealots and their relationship to an earlier movement, the Maccabees, has also been the object of much dispute.
This dispute always involves interpreting histories of the period written by Flavius Josephus, who is usually referred to as Josephus. Josephus was a historian who wrote several books (in Aramaic and Greek) about the Jewish revolt against Roman rule and about the Jews from their beginnings in ancient Israel, and the only contemporary source who described the revolt
Josephus wrote the only account of the activities of the Sicarii. In his writing he distinguishes the Sicarii from the Zealots, but what he means by this distinction has nevertheless been the basis for much discussion. Later references can be found in the Gospels and in medieval Rabbinic literature.
A number of prominent scholars of both Jewish history and the history of Roman rule in Judea have concluded that the Zealots and the Sicarii were not the same group, and that Josephus did not use these respective labels interchangeably.
Sources consulted include:
Richard Horsley, "The Sicarii: Ancient Jewish "Terrorists," The Journal of Religion, Vol. 59, No. 4 (Oct. 1979), 435-458.
Morton Smith, "Zealots and Sicarii, Their Origins and Relation," The Harvard Theological Review, Vol. 64, No. 1 (Jan., 1971), 1-19.
Solomon Zeitlin. "Masada and the Sicarii," The Jewish Quarterly Review, New Ser., Vol. 55, No. 4. (Apr., 1965), pp. 299-317.