Leave to thinking about that to someone at PolishForums.com. I had already heard that "Kacz" could be "Katz". Today, I (as far as I recall) got to thinking that maybe "Kacz-o-row-ski" may be "ה]בן [ה ]כ"צ ורב]". By breakdown:
- "ה]בן]" is "ski" ("[the] son")
- "ה ]כ"צ]" is "Kacz" ("[the] kohen tzedek")
- "ורב" is explained by the fact that "rov" is "Rav" or "Rabbi" or "great" in Ashkenazi Hebrew and standard Yiddish. So, John Paul's maternal family may well have come from a rabbi who was a kohen, a great man, or both.
Incidentally, there may have been another Jewish Pope: Benedict XVI, who was apparently a descendant of Rabbi Judah Loew. By the way, I can safely say that I had taken Matthew 23:8-10 too far, although old habits die hard and I still feel guilty or unsure about using words like "rabbi" and "pope".