In spite of the fragmentary character of the evidence and the disparateness of the literary sources, it can be said that the Second Commonwealth saw the multiplication of Jewish groups or tendencies mostly differentiated, on the basis of their common Judaism, by their various ways of relating Jewish religious concerns to the political situation of Greco-Roman Palestine. The phenomenon intensified and gave rise to grave tensions during the Hasmonean period, when issues debated related to the very interpretation of Torah and to the alternatives defined by assimilation/Hellenization or separatism. The ensuing malaise grew and reached a climax in 63 B.C.E. when the Romans awarded the high priesthood to their favorite, Hyrcanus II, and imprisoned the legitimate candidate, Aristobulus II.
The Pharisees, so much and so unjustly caricatured in Christian literature, developed from about 150 B.C.E. as a loose association of pietists from the middle and lower classes, holding the ancient traditions of Israel as solely authoritative but accepting a whole set of “traditions of the fathers,” which were to be referred to as the “Oral Torah” by later rabbis. They distinguished themselves by their careful observance of the law as well as by their flexibility in adapting the law to new circumstances. In the process, two schools emerged among the Pharisees: the rigid school of Shammai and the more lenient school of Hillel. Their central teachings were to be incorporated in the rabbinic tradition—ideas concerning the soul's immortality and the resurrection of the dead, Providence, retribution, angels. As the Hasmonean leaders and their supporters became increasingly Hellenized, Pharisees dissociated themselves from them, thereby ceasing to be a political force and constituting themselves as a group of purely religious leaders, thus passing from politics to piety. Eventually the Pharisee merged with the rabbi, and the Tannaim inherited the Pharisaic approach to Judaism, especially the approach characteristic of the school of Hillel.
The high priestly office was under the control of the Sadducees, who claimed some continuity with the times of Solomon. They belonged to the aristocracy. Like the Samaritans, they did not appeal to the traditions of the fathers and they favored a sort of literalism in interpreting scripture. Sadducees thought that purity laws did not apply to the daily life of all people but only to the Temple and its priests. They consistently denied the central teachings espoused by the Pharisees and were more open to Hellenization. When a Hasmonean leader took over the high priesthood sometime between 152 and 140 B.C.E. many of the Sadducees, out of resentment, seem to have moved to Qumran. Thus the priestly Sadducees lost their influence in favor of the learned Pharisees, and indirectly contributed to the later shift from Temple to Torah.
Two further important groups, possibly identical, rounded off the backdrop against which Christianity arose. They developed ascetic practices and mystical ideas, and perhaps encouraged the messianic visions that led certain activists to the two revolts against the Romans. The Essenes were described by Philo, Josephus, and Pliny as a sect entered through initiation; practicing collective ownership, frugality, and asceticism; keeping its distance from the Temple but emphasizing ritual purity. Some scholars recognize in them Pythagorean features. They disappeared after 73 C.E. Philo also mentions a Jewish sect in Egypt, the Therapeutae, similar to the Essenes.
The Dead Sea Sect (Qumran) presented basically the same features as the Essenes with the addition of sharp messianic and apocalyptic overtones. They actively prepared for the coming age when a clear distinction would emerge between temporal and priestly authority. They were prone to castigate the priest officiating in the Jerusalem Temple. Their relation to the Sadducees and to the Essenes is still debated but seems to have been real in view of their common anti-Hasmonean bent.
Another group, called the Zealots by Josephus, opted for an activist, even military solution to the national predicament. Either
recruiting from all the previously mentioned factions, significantly perhaps from among the Shammaite Pharisees, or made up of a mere coalition of brigand bands from the countryside pushed out of their lands by the Roman advance in the late sixties, they made the headlines for a short while. Sporadic outbursts of activity culminated in the first revolt of 70. The Zealots vanished definitively after 135, as did numerous sects, while the legacy of the Pharisees, as pointed out above, survived in Rabbinic Judaism.
It must be emphasized that all these groups, and these are only the most important ones, were sharing a common history and the common experience of election, covenant and law, Temple, and exile and return, in addition to the accumulated frustrations under foreign rule. They were parties (haireseis, according to Josephus) holding different views and practices within the same ethnic and religious group. It is mainly in the kind of response to common frustrations that they differed between themselves and slid into factionalism. Popular discontent and religious expectations combined to create those associations espousing various options, some encouraging activism, others withdrawal, yet others collaboration. The constellation they constituted represented the nourishing soil for both Rabbinic Judaism and early Christianity, while the various interpretations of Jesus, encountered from the start among the Christian community, doubtless reflect various tendencies within the Jewish Palestinian society itself.