Split of Christianity and Judaism

Christianity began as a movement within Second Temple Judaism, but the two religions gradually diverged over the first few centuries of the Christian Era, and the Christian movement perceived itself as distinct from the Jews by the fourth century. Historians continue to debate the dating of Christianity's emergence as a discrete religion apart from Judaism. Philip S. Alexander characterizes the question of when Christianity and Judaism parted company and went their separate ways (often termed the parting of the ways) as "one of those deceptively simple questions which should be approached with great care". According to historian Shaye J. D. Cohen, "the separation of Christianity from Judaism was a process, not an event", in which the church became "more and more gentile, and less and less Jewish". Conversely, various historical events have been proposed as definitive points of separation, including the Council of Jerusalem and the First Council of Nicaea.

Historiography of the split is complicated by a number of factors, including a diverse and syncretic range of religious thought and practice within Early Christianity and early Rabbinic Judaism (both of which were far less orthodox and theologically homogeneous in the first centuries of the Christian Era than they are today) and the coexistence of and interaction between Judaism, Jewish Christianity, and Gentile Christianity over a period of centuries at the beginning of Early Christianity. Some scholars have found evidence of continuous interactions between Jewish-Christian and Rabbinic movements from the mid-to late second century CE to the fourth century CE. The first centuries of belief in Jesus have been described by historians as characterized by religious creativity and "chaos".

The two religions eventually established and distinguished their respective norms and doctrines, notably by increasingly diverging on key issues such as the status of "purity laws" and the validity of Judeo-Christian messianic beliefs.

Hellenistic Judaism
Shaye J.D. Cohen writes that "Even the most Hellenized of Jews, e.g. Philo of Alexandria, belonged to Jewish communities that were socially distinct from “the Greeks,” no matter how well these Jews spoke Greek, knew Greek literature, and assimilated Greek culture high and low."

Second Temple period
There were numerous first-century Jewish sects interpreting the Torah (the Talmud refers to twenty-four such sects).

Jewish Christianity
Most historians agree that Jesus or his followers established a new Jewish sect, one that attracted both Jewish and gentile converts. According to New Testament scholar Bart D. Ehrman, a number of early Christianities existed in the first century CE, from which developed various Christian traditions and denominations, including proto-orthodoxy. According to theologian James D. G. Dunn, four types of early Christianity can be discerned: Jewish Christianity, Hellenistic Christianity, Apocalyptic Christianity, and early Catholicism.

The first followers of Jesus were essentially all ethnically Jewish or Jewish proselytes. Jesus was Jewish, preached to the Jewish people, and called from them his first followers. According to McGrath, Jewish Christians, as faithful religious Jews, "regarded their movement as an affirmation of every aspect of contemporary Judaism, with the addition of one extra belief-that Jesus was the Messiah."

On the subject of the separation of early Christian belief from Judaism, Shaye J. D. Cohen writes that early Jewish believers in Christ "had a choice: they could join the emerging Christian communities which were being populated more and more by gentile Christians; or they could try to maintain their place within Jewish society, a stance that will become harder and harder to maintain as the decades go by; or, if they were uncomfortable among non-Jewish Christians and non-Christian Jews, they could try to maintain their own communities, separate from each of the others." He writes that the New Testament shows that, among Christ-believing Jews in the first century, the norm was to join the emerging gentile-populated Christian communities. But as these communities became more hostile to non-Christian Jews, the Christ-believing Jews were pushed to compromise either their Jewish identities or their belonging within the Christian communities.

By the second century, Romans regarded Christians and Jews as separate communities, persecuting Christians without targeting Jews. Second-century Christian writers regularly accused the Jews of collaborating with the Romans in their anti-Christian persecutions. Eusebius attests to a Christian converting to Judaism in order to escape Roman persecution. The opposite is true, too; when the Romans persecuted Jews, they ignored Christians.

Historiography
Daniel Boyarin describes a traditional (and in his view, errant) understanding of Judeo-Christian origins in 1999's Dying For God: "Not long ago, everyone knew that Judaism came before Christianity. The story would go that Christianity developed out of the 'orthodox' Judaism of the first century, rabbinic Judaism, and either deviated from the true path or superseded its ancestor." He writes that this narrative, which he calls the "old paradigm", was propagated in "more or less the same" form by both Christian and Jewish scholars, with an understanding of pre-Christian Jews that anachronistically reduced their religious diversity into a single "Judaism". Israel Yuval described the paradigm as seeing early Christianity "only as influenced and not as influencing". In the late 20th century, scholars began to favor a more complex view of pre-Christian Judaism, and came to understand early Christianity and Rabbinic Judaism as "sister religions that were crystallized in the same period and the same background of enslavement and destruction."

Parting of the ways
The term parting of the ways refers to a historical concept figuring the emergence of Christianity's distinction from Judaism as a split in paths, with the two religions becoming separated like two branching roadways "never to cross or converge again". While most uses of the metaphor consider Christianity and Judaism to be two equally-important roadways, some use it to describe Judaism as the main "highway" from which Christianity forked. The metaphor may also refer to an interpersonal "parting", as in human relationships when two parties no longer see eye to eye and decide to "go their separate ways".

Reed and Becker describe a "master narrative" of Jewish and Christian history that is guided by the parting concept, which describes a first-century Judaism characterized by great diversity, with exchange between Christ-believing and non-Christ-believing Jews, that was fundamentally changed in the wake of the Second Temple's destruction and the later Bar Kokhba revolt of the Jews against Roman rule, after which Christianity and Judaism "definitively institutionalized their differences". The master narrative recognizes this period as the point from which Judaism's influence on Christianity was limited to the Jewish scriptures that the Church held as their Old Testament.

The parting of the ways is the most commonly-used metaphor in contemporary scholarship on the topic of Christianity's historical distinction from Judaism, and the notion has been subject to a number of debates, criticisms, and metaphorical adaptations from scholars. Judith Lieu has argued for a "criss-crossing of muddy tracks which only the expert tracker, or poacher, can decipher" over the parting metaphor, while Daniel Boyarin describes a continuum along which one could travel rather than a divide or partition between rabbinic Judaism and Christianity. Scholarly works on the matter of the concept of the parting of the ways have been published under such titles as "The Ways That Never Parted", "The Ways That Often Parted", and "The Ways That Parted".

Reception and criticism
In the Introduction to The Ways That Never Parted, Annette Reed and Adam Becker identify two fundamental assumptions guiding the parting model: that "Judaism and Christianity developed in relative isolation from one another," and that "the interactions between Jews and Christians after the second century were limited, almost wholly, to polemical conflict and mutual misperception." Reed and Becker, however, describe a literary and archaeological record of interaction between Jewish and Christian communities that suggests a "far messier reality" than that suggested by the parting concept, citing theological literature in which Jews and Christians reacted to one another's theologies and religions. Shaye J. D. Cohen, who upholds the parting narrative, argues conversely that "the notion of 'the parting of the ways' does not in the least suggest that Jews and Christians stopped speaking with each other, arguing with each other, and influencing each other," and that reactions to Christianity in rabbinic scholarship neither prove nor disprove such a parting, and only prove that Jews and Christians continued to speak with one another after their parting. Cohen also argues that "There was no parting of the ways between gentile Christians and non-Christian Jews for the simple reason that their ways had never been united."

Philip S. Alexander describes motivations for both Christian and Jewish scholars in upholding and propagating the parting of the ways: "The attempt [to lay down a norm for Judaism in the first century] barely conceals apologetic motives-in the case of Christianity a desire to prove that Christianity transcended or transformed Judaism, in the case of Jews a desire to suggest that Christianity was an alien form of Judaism which deviated from the true path."

Other metaphors
Historians of Early Christianity have been "inventive in creating metaphors" to explain and illustrate the emergence of Christianity from Judaism. Philip S. Alexander posited a Venn diagram to compare to the process of Christianity's differentiation from Judaism, with the two religions beginning as two overlapping circles, which gradually moved apart until they were entirely separated. Daniel Boyarin commends Alexander's Venn diagram image for complicating the dominant "parting of the ways" notion of Christian historical distinction, but regards the metaphor as still being too simple for the "reconfiguring [of the historical narrative of Christianity's emergence] that needs to be done". Among the several metaphors proposed by James Dunn is the metaphor of a textile, which illustrated first-century Judaism as a woven textile, and Early Christianity as one of its fibers. Both Dunn and Daniel Boyarin have used body of water metaphors: Dunn described Rabbinic Judaism and Early Christianity as two currents that eventually carved separate channels from the stream of ancient Judaism, and Boyarin described Early Christianity as one of many first-century Jewish movements that flowed out from one source, like ripples on a pond's surface.

Kinship
Metaphors of family and kinship "dominated" nineteenth- and twentieth-century academic discussion of the relationship between Judaism and Christianity, and are still used in contemporary scholarship. Daniel Boyarin calls the understanding propagated with the use of this metaphor "the old paradigm". A mother-child metaphor was particularly common in the nineteenth century, with Christianity as the child born from and nurtured by Judaism. Adele Reinhartz criticizes this formulation for its implication that Judaism was a single entity, when in fact it was "an ever-shifting set of groups". Boyarin identified the mother-daughter metaphor, which he attributes to Jacob Lauterbach, as "a typical example of how the myth [of Judaism and Christianity as 'self-identical religious organisms'] works". Alexander described the historical reduction of pre-Christian Jewish religious diversity into the singular entity of "Judaism" as taking place in two distinct ways: through the anachronistic "retrojection" of Rabbinic Judaism onto first-century Pharisaic Judaism, and through the assumption that all first-century Jewish religions shared some common features that allowed them to be joined into a single religion.

Alan Segal proposed a sibling metaphor as more accurate than that of the mother and daughter. Segal's metaphor compares the two religions to the biblical twins Jacob and Esau, "Rebecca's children", in acknowledgment of their "mother": Second Temple Judaism. Daniel Boyarin identified this interpretation of the two "new" religions as "part of one complex religious family, twins in a womb, contending with each other for identity and precedence, but sharing with each other the same spiritual food" for at least three centuries, as a new scholarly paradigm that overtook the "old paradigm" of the mother-daughter metaphor. Boyarin suggested that kinship metaphors should be abandoned altogether, because they erroneously imply a separation of first-century Judaism and Christianity as organic, definite entities. He proposed "a model of shared and crisscrossing lines of history and religious development", describing Judaism and Christianity in late Antiquity as two points on a continuum, with Marcionites and non-Christ-following Jews at each end, respectively.

Social
Shaye J. D. Cohen argues that, while theological disputes between Jews and followers of Christ contributed to the social separation of the two groups, the disputes themselves had no direct connection to the parting; instead, the split of Christians from Jews was a process of social separation.

Bar Kokhba revolt
Simon bar Kokhba led the Jews of Judea in a revolt against the Roman Empire from 132–135 CE. The Romans, either as a cause of or in response to the uprising, initiated a persecution against Jewish religious observance. During this campaign, the Romans ignored the Christians, considering them to be separate from the Jews.