When Jesus reached the famous well at Shechem and asked a Samaritan woman for a drink, she replied full of surprise: "Jews do not associate with Samaritans” (John 4:9). In the ancient world, relations between Jews and Samaritans were indeed strained. Josephus reports a number of unpleasant events: Samaritans harass Jewish pilgrims traveling through Samaria between Galilee and Judea, Samaritans scatter human bones in the Jerusalem sanctuary, and Jews in turn burn down Samaritan villages. The very notion of “the good Samaritan” (Luke 10:25-37) only makes sense in a context in which Samaritans were viewed with suspicion and hostility by Jews in and around Jerusalem.
It is difficult to know when the enmity first arose in history—or for that matter, when Jews and Samaritans started seeing themselves (and each other) as separate communities. For at least some Jews during the Second Temple period, 2Kgs 17:24-41 may have explained Samaritan identity: they were descendants of pagan tribes settled by the Assyrians in the former northern kingdom of Israel, the region where most Samaritans live even today. But texts like this may not actually get us any closer to understanding the Samaritans’ historical origins.
The Samaritans, for their part, did not accept any scriptural texts beyond the Pentateuch. Scholars have known for a long time about an ancient and distinctly Samaritan version of the Pentateuch—which has been an important source for textual criticism of the Bible for centuries. In fact, a major indication for a growing Samaritan self-awareness in antiquity was the insertion of "typically Samaritan" additions into this version of the Pentateuch, such as a Decalogue commandment to build an altar on Mount Gerizim, which Samaritans viewed as the sole “place of blessing” (see also Deut 11:29, Deut 27:12). They fiercely rejected Jerusalem—which is not mentioned by name in the Pentateuch—and all Jerusalem-related traditions and institutions such as kingship and messianic eschatology.
The aggressive expansion of the Jewish Hasmonean kingdom and the destruction of the sanctuary and the city on Mount Gerizim in 110 B.C.E. further deepened the rift between Samaritans and Jews. Countering the claims of the “Jewish heretics in Jerusalem,” the Samaritans consequently saw and still see themselves as the true Israelites and “keepers of the covenant” (shomronim or shomrim in Hebrew, echoing the Hebrew name for Samaria, Shomron).
Despite all these polemical traditions, however, Samaritans and Jews had much more in common than we might think. Both based their faith on the Pentateuch. Rather than a "split" at one particular moment, the relation between Samaritans and Jews is characterized by a long process of alienation and parallel development between the fourth–third centuries B.C.E. and the fourth century C.E. Because the Samaritans only accepted the Pentateuch, they fervently advocated Yahwistic monotheism and, above all, held Moses and (to a lesser extent) Joshua in particular esteem. Like the Jews in Jerusalem, the Samaritans followed a hereditary priesthood and accepted only a single central sanctuary. Whatever their historical origins as a distinct group, the Samaritans are probably best seen as one among the diverse range of religious communities of postexilic Judaism.
In some contrast to the passage in John cited above, New Testament texts usually share the Jewish anti-Samaritan stance (Matt 10:5, Luke 9:51-55) or show interest in non-Samaritan inhabitants of the region, such as Simon Magus (Acts 8:9-13, Acts 8:18-24). During the fourth–sixth centuries C.E., many rabbinic discussions about the Samaritans confirmed their piety but also emphasized fundamental differences in observance of certain laws, including those of marriage and of the levitical priesthood.
Marginalized by their Jewish compatriots and often violently oppressed by Byzantine authorities (especially under Justinian), Samaritans nevertheless shared many features of a common late-antique culture. From the Hellenistic to the Byzantine period, we have numerous indications of a widespread, Greek-speaking Samaritan diaspora (for example in Delos, Egypt, Asia Minor, and Italy). The situation of the Samaritans first improved under Islamic rule, but in the course of time, their numbers dwindled. Today, only a few hundred Samaritans live on Mount Gerizim and in Holon, near Tel Aviv.