The origins of Islam are fascinating, because the religion is critically important in the modern world, but its genesis within history is surprisingly vague for its first decades. Muslims have their own historiagraphy, and some Western historians, such as Hugh Kennedy transmit this narrative with high fidelity, albeit shorn of sectarian presuppositions and strongly leavened with Western positivist methodologies. His books The Great Arab Conquests and When Baghdad Ruled the Muslim World: The Rise and Fall of Islam’s Greatest Dynasty are rather good in my opinion.
An alternative view is presented by revisionist scholars, who in the process of revising Islamic history tear apart its basic foundations, at least from a Muslim perspective. Their views can be found in works such as The Hidden Origins of Islam. This school of scholars contends that much of Islam’s early history, basically before 700 A.D., is myth-making that dates from the Abbasid period (>750 AD). An analogy here might be made to Republican Rome. The city emerges prominently in history only in the 3rd century B.C., so much of centuries of Roman history which are referred to by later writers are difficult to corroborate. Presumably many of the figures of these earlier periods, such as Cincinnatus, may have been historical, but more often than not it is likely that details of their life served as moral exemplars for republican political leaders.
Similarly, a basic thrust of the revisionists in relation to Islam is that the idea of Muhammad is far more important than the details of who he really might have been. Even the milieu of Muhammad, a desert merchant, may have been manufactured to give him a particular aura. To reduce one line of scholarship to its essence Islam emerged as a national religion of Christian Arabs who had long been on the margins of the Roman and Persian worlds decades after the time of Muhammad. The construction of the Muhammad myth, and relocating sacred sites to a area far outside Roman control and influence (Mecca & Medina), may have been motivated by considerations of distancing from the Greco-Roman and Persian cultural traditions which they were attempting to absorb and supersede.
One aspect of the mythos of Muhammad is that he grew up as a primal monotheist in a pagan land. The revisionists reject this, and suggest that Muhammad was a Christian, in an Arabia where Christianity and Judaism were the dominant elite religions. No doubt there were other religious sects, and the influence of Zoroastrianism was also likely, but organized paganism as depicted in Mecca may have been a propaganda device. There are precedents for this line of thought, some scholars have argued the same for the late survival of paganism in Sweden (in comparison to Denmark and Norway), suggesting that in fact it was a scurrilous attempt by Western Christians to besmirch Eastern Orthodox believers, who were much more numerous in this region of Scandinavia.
I don’t personally take a strong position here. It seems likely that the revisionists go too far, but I do think that a quasi-state paganism in Arabia in the year 600 A.D. is implausible in light of what we know about other regions of the world on the Roman frontier. The dominant forms of religion in Muhammad’s world probably was Christianity, with roles for Judaism, Zoroastrianism, and various gnostic cults. Pagans still remained, but they were likely a marginal residual, not a threatening elite force as depicted in Islamic tradition.
So, with all this historical context in place, it has come to my attention that there are some peculiarities in the male paternal lineage of descendants of the clade L859+, the dominant haplotype among the Quraysh, Muhammad’s tribe. This lineage, L859+ is a clade within haplogroup J1, which includes the famous Cohen modal haplogroup. On the L859+ tree above you see that the Qurayshi’s are a brother clade to ZS22012. This is traditionally a Jewish lineage. None of this “proves” anything, but it’s interesting and suggestive. If the revisionist are right, and Muhammad grew up in a world dominated by Jews and Christians, it would not be implausible if he himself was of Jewish background in some fashion. Or, that Arab Jews and Arab Christians had a fluid and permeable cultural relationship, and both interacted with the large Jewish community of the Middle East of the period, where some Arab Christians descended from Jews.