Black Hebrew mythology originates from the same place as Black Jewish synagogues, which furthermore is not terribly different from black perspectives on Islam. All of these groups came to prominence in the first decades of the twentieth century, with the Muslims organized into the Nation of Islam a few decades later. Black Americans emerged from slavery, where they were often given a purposefully censored view of Christianity by their enslavers, combined with analogies spread amongst themselves to the sacred history of Moses leading the Jews to freedom. Excluded from white churches and seminaries, they often saw the white Christian establishment as having created an institutional hypocrisy, and sought out alternative ways of defining themselves as an ethnic-national group.

Because Jim Crow racial norms held that black people were a separate nation “from Africa” in an otherwise European continent, Jews were an easy reference point, considering how they admitted to non-European origins. As whites drew legal boundaries to prevent blacks from intermarrying or participating in civic life, the success of the Jews despite self-imposed racial boundaries was again an easy reference point. Blacks who attempted to practice Judaism were accused of mimicry and fraud by ethnic Jewish rabbis, which immediately led to the rhetoric you probably heard from Ye/Kanye West or Kyrie Irving this week:

The assertion that Judaism was uniquely suited to black people went hand in hand with the claim by some black Jews that Jews of European ancestry were in fact frauds or "interlopers:' Prophet Cherry, for example, often quoted Revelation 3:9 ("Behold, I will make those of the synagogue of Satan who say that they are Jews and are not, but lie, behold, I will make them come and bow down before your feet and learn that I have loved you") in support of his belief that white Jews were religious impostors. Rabbi Arnold Ford taught that the "real" Jews were black people, while Jews of European descent were said to be "offshoots" of the original lineage of black Jews or converts who had received the religion secondhand from Africans.

However, these quotes are from 100 years ago and were spoken by black rabbis! You can see a 1923 photo of a Black Jewish women’s choir in the article I am quoting this from. As that article notes, this is very similar to the Nation of Islam “Yakub” mythology of the 1960s in its provocative intent.

Some Black Americans converted all the way to practicing Judaism and continue to practice it today. The Jewish community has grown much more understanding of Black Judaism over the decades, which has led to racial integration from the ethnic Jewish side and better understanding of Jewish historical orthodoxy on the Black Jewish side, although relations remain awkward sometimes (you can see discussions on this on Jewish news sites). You also mentioned the Nation of Islam, which underwent a similar process; the group began when Americans in general had a poor understanding of Islam, so it used Muslim and Jewish symbols freely, but now the original branches of that group promote orthodox Islam and dialogue with Judaism.

Outside these groups, though, rhetoric about an African Israel continued to mix with other beliefs about African identity and racial unity. This rhetoric is often eclectic, meaning there is no institutional organization to it, and no one person who propagates this kind of mythology; it circulates in in-person lectures and in self-published books, and academic research about it is similarly scattershot. Unfortunately, although Black Hebrew mythology originated as a legitimating device for black expression of Judaism, after being divorced from its initial context for decades and appropriated by wholly different groups with different motives, it has now become a flimsy justification for hateful antisemitic remarks.

I'm seeing a lot of secondary questions here about these ideologies, so I'm going to explain this how my student who believed in this mythology explained it to me.

Essentially, we are talking about separate sections of history being co-opted by social movements in the 20th century, as stated above. Through studying scripture, however, one sees the problem immediately, in the book of Genesis (I'm taking from KJV, so please spare me any Biblical commentary, this is obviously massively abbreviated and simplified, as all three umbrella Abrahamic religions are still arguing thie point to this day about the location of Eden):

And a river went out of Eden to water the garden; and from thence it was parted, and became four heads. The name of the first is Pishon; that is it which compasseth the whole land of Havilah, where there is gold; and the gold of that land is good; there is bdellium and the onyx stone. And the name of the second river is Gihon; the same is it that compasseth the whole land of Cush. And the name of the third river is Tigris; that is it which goeth toward the east of Asshur. And the fourth river is the Euphrates.

So, needless to say, this is a broad swathe of land in the Middle East (see the map linked below) and anyone claiming to be certain about the location of Eden will need to produce some evidence from not only multiple cultures but also multiple missing historical sources. That being said, the stem of this belief about Eden being somewhere in modern day Iraq, which most people accept, seems to come from some semihistorical knowledge of the descriptions of the Gardens of Babylon on the part of the believers of this theory that I have spoken to, including my former student and just regular Christian theology. However, as a student of religious myths, I find the overlapping dates here problematic.

If you consider that the Torah has it correct, and modern day Jewish people extend back to enslavement in New Kingdom Egypt (a theory which by the way has never been proven in the archeological record and is now mainly rejected by scholars, because it's been shown that the stories were written centuries after the events) then the Bible holds water, and this is all just a debate about skin color. According to those who believe in this theology of Black Hebrew Israelites being the basis for Judaism, however, this is a "well crafted lie" and continues to be used to oppress Black people in the United States. As I told my student and continue to tell others to this day, this is hugely antisemitic. Regardless of the origin of the Jewish faith, calling the belief of millions of people a continuing conspiracy is just blatantly stupid.

That being said, historically speaking, it's hard to nail down exactly where Eden would have been, and it does matter to a lot of Radical Hebrew Israelites, who even Southern Poverty Law Center identifies as a radical group worth attention. If, as those who I have talked to put it, Eden was actually in, say Upper Egypt, or as far south as Ethiopia, how might that effect the modern belief in Christianity, in its origins, and in its foundations? It's a question we talked about a lot, and I still don't have an answer for it. I think, however, it shows something more interesting.

If you consider the timeline, the stories in Genesis and Exodus pass through a good 1.4 billion years of evolution, all the way to the birth of "civilization" in the Middle East around 6500 BCE. If you then consider that Hebrews and Israelites did not begin worshipping their YHWH until at least 2500 BCE, then the vast space between Genesis and Exodus makes a lot of sense in that it's about the systems of agriculture coming to some (and not to others) specifically the kingdoms in Mesopotamia and not further west in Canaan and modern Israel.

However, that is pure speculation. This is a story that is still being processed, and regardless, I think it's important to have perspective. Whether or not the Jewish faith originated in the Holy Land, or whether it originated further south or east or west or north, is immaterial. Jewish people now do not deserve the disrespect being slung around by Kanye, and his facts are, at best, a stretch.

Map:

Potential Names for Eden Rivers

Sources:

https://www.jstor.org/stable/3317528

https://www.chabad.org/parshah/article_cdo/aid/3082157/jewish/Where-Are-the-Four-Rivers-that-Come-from-Eden.htm

https://www.splcenter.org/fighting-hate/extremist-files/group/radical-hebrew-israelites