Actually, a leading hypothesis among researchers is that the Jews in the Rhineland came from Italy, although I personally don't think it's possible to prove that except perhaps for some specific families.
As we see with the ancient DNA from various places of the Roman empire, people similar to Italians were everywhere. So I'm pretty sure that Romans in the wider sense did convert, there are even hints for it being in Italy, which seems to be quite likely, but that's hard to prove, like you say.
It's true that the first evidence of Jews, from Cologne, is from the 4th century, when the area was not yet Christian, so a few conversions could have occurred then, but if Greek and Roman men hesitated to undergo circumcision to convert, one of the reasons Christianity was more attractive, I don't think pagan Germans would have necessarily been too happy about it either. Women might be a different story.
Wouldn't say so, they were the tougher guys quite often and might have converted for a variety of reasons, including socio-economic advantages and love, like in the case I quoted from many centuries later. Also, it mustn't have been that many. If the Jewish community up in the North was always rather small, what it seemed to have been, even a very small contribution per generation would have made a big difference on the long run. Whereas on the other hand, the Jewish converts to pagan and Christian denominations would have just disappeared in the gene pool of the majority with few traces left.
It is impossible to tell, imo, from a few scattered instances, how many people did convert to Judaism in such early days. What we do know is that there was a lot of mass rape of Jewish women during the Crusades. I personally think it's far more likely that Jewish R1b line resulted from such violence. You're of course entitled to believe that it didn't, and that, of course, rape during raids or even what they might have considered a wa,r would be more common among Slavic men than among German men.
The crusaders were, on average, quite religious and pious people. Its not as much about "Slavic vs. German" or something like that, this would become a nasty debate which is not my intention, but the crusaders of the high Middle Age. Also, I really doubt another thing, namely that a lot of children which were the result of such mass rapes would have survived among the Jews, in all times. Some would, but not a lot and especially not after such an incidence.
In Italy during that war, when such things happened, Catholic dogma or not, a lot of abortions were performed.
And Jews have no such dogma. Read up the Rabbinic tradition about it.
I often think the German women must have done the same after the Russian mass rape of the women in Berlin and the other Russian territories after their arrival. If not, then some analyses showing "Slavic" in modern East Germans might have one more explanation to add to the rest.
In Germany there are two such incidences on a bigger scale in recent history. One after the 1st World War in Western Germany (Rhineland, French and Colonial troops) and the second after the 2nd World War in the West, but especially in the Soviet East. In both cases many such children were born and raised by their German mothers, but its hard to get percentages in relation to abortions or infanticide and the total impact was very, very low everywhere. So it had no real influence on the German population overall, not at all.
Its worth to note that the worst rapists in the Red Army were either alcoholised, acted under group pressure or were, to a large extend, no Slavs, but actually people from the ethnic minorities of Russia. There were a lot of cases in which (ethnic) Russian officers warned women before they were raped, that after the fighing troops, which were under their control, "in the evening the scum will come" with the baggage and they should hide. And most women described the situation in the same manner: First they got drunk, then they came in groups...
Of course all soldiers are inclined to rape, especially in the situation of a brutal war, in the face of a hated enemy and if they don't know what's coming next for them, whether they survive the next day. But some more than others, depending on the circumstances, that's a statistical reality.
Yet the German mercenaries in the 30 year war might not have been the worst around, there were worse even in that war, but they did their share of brutal atrocities among their kinsmen too. So this can happen between a lot of groups and even among people of the same ethnicity of course.
But I think in Medieval Germany, among the German crusaders, they might have done all kind of things, but the majority was really believing in their cause. And they thought that every action would be seen by god and they didn't wanted to befoul their holy cause by acts which were deemed to be sinful. With that I don't want to say it didn't happen, but I don't think it was that influential.
I've forgotten how much non-Z93 R1a there is in Jews. I'd have to go back and check. Also, there are some other y lines in the area. Conversion of women would have been even more possible in the east because there were non Christian areas much later.
I think most of the European conversion of women happened in the Roman empire already and in later times there was much less of a sex bias. So the original founders were Jewish men from the Near East, which met on their journeys Greek and Roman women (mtDNA seems to point in that direction, doesn't it?) which they took as wives. That core group spread in various directions, but one of the most important ones happened to end up in the North, the Frankish kingdom. There admixture with locals of later French and German ancestry took place, before they moved to the East, towards Poland, where the majority of the surviving strains from the North mixed and a founder effect occured.
Regardless, although IBD analysis isn't foolproof, it clearly shows Slavic intrusion into the Ashkenazim, contrary to the levels it shows for western Europeans, Italians, etc.
Sure, its the newest contribution, from after the big medieval bottleneck.
The whole question of Jewish genetics is not going to be answered until we have quite a few late first millennium B.C.E. and Classical Era Jewish samples from not only Israel but the Jewish diaspora. Until then it's just one person's speculation versus another's. That's why I rarely discuss it anymore.
Agreed.
