So my distant cousin would like to know my rationale for saying "Prussia" rather than the "generally held" South Russia.
So I politely pointed the cousin at the above link, and suggested reading Dyck's history, and maybe Klassen's book (_Mennonites in Early Modern Poland and Prussia_).
I love history, so it is a joy to have an excuse to read more, and a frisson of wonderment to feel like I am reading about my relatives. But I understand that even many genealogists find history incredibly boring. Still, genealogists need to know the timeline of migrations of Their People, or they will get sucked into really embarrassingly obvious errors.
I'm betting I'll be getting another message shortly about why I think the man's son (who was born after the first settlement was established in Russia) was also born in Prussia. I'll need to dig around to remember why I thought that.