Theory About My yDNA Origins

I had a yDNA 37 marker test done with Family Tree DNA back in 2013 hoping to find a connection to my Miller family in Germany. Unfortunately, I only ended up with one match and that was a very distant match with a completely different surname from Spain. My yDNA haplogroup turned out to be J-M172, having nothing to do with any German haplogroup where my yDNA line is from. Family Tree DNA says of the origins of this haplogroup:

"...northern Middle East, west of the Zagros Mountains in Iran, to the Mediterranean Sea. It later spread throughout central Asia and south into India. J-M172 is tightly associated with the expansion of agriculture, which began about 10,000 years ago. As with other populations with Mediterranean ancestry, this lineage is found at substantial frequencies within Jewish populations.  J2 is also one of the main Haplogroups found among Arab populations."

I've documented my direct male Miller line back to around 1670 in Germany. Why would it be showing up as Middle-Eastern? Why would my closest match have ancestry in Spain? I thought of a theory of what this might be telling me but it's unlikely I'll ever be able to confirm it.

My theory is that, around 100 years prior to what I have documented for my Miller ancestry, a male line ancestor did actually migrate from Spain to Germany. Why would he do that? Why would his yDNA show as Middle-Eastern? The answer to these questions is the Spanish Inquisition.

"No one expects the Spanish Inquisition!" is the line from Monty Python's Flying Circus. I certainly didn't!

I am not an expert in the subject but I'll provide some basic background. Large areas of Spain were controlled by Muslims up until around the year 1250 when it was mostly taken over by Christians. Jews and Muslims were tolerated at best, living in a small area while a few remained in larger cities.

In the late fourteenth century, anti-Jewish violence spread around the land. Those who would not convert to Christianity were killed. Those that converted were known as "Conversos". Many Conversos would more accurately be described as Crypto-Jews. They put on a public face of being Christians but kept the Jewish faith and customs in the home.

In the late fifteenth century, King Ferdinand II and Queen Isabella of Spain believed corruption in the church was caused by Jews remaining among their population and they were killed or forced to leave.

My theory is that my direct male line ancestor was either Jewish or Muslim living on the Iberian peninsula and was eventually forced to leave for greener pastures in Germany. One piece of evidence in my yDNA that supports this belief is that this closest yDNA match, whose ancestry is in Spain, is a genetic distance of 2 at 25 markers. According to Family Tree DNA, the estimated number of generations to go back to find a common ancestor with this match would be a 50% chance at 12 generations, 68% chance at 14 generations, 80% chance at 20 generations and 90% chance at 24 generations.

My furthest documented male line ancestor is 10 generations back around the year 1670. At an average of 25 years per generation, that would put 15 generations to around the year 1495. This is right at the height of the Inquisition.

Do I have proof that my theory is true? No. Still, history and DNA does line up. It's my best theory yet. What do you think? Am I missing some bit that would either prove or disprove this theory? Let me know your thoughts!

--Matt