At least Zalman didn’t deny that the Neviim, Tzedukim, Hellenizers and Karaites existed. Purim took place because our ancestors were out partying with Achashvarosh! Menashe, perhaps the most evil king in our history, ruled the longest and brought avodah zora into the Bais Hamikdash!The Gemorra describes, how in the times of the Bais Sheni, the office of Kohen Gadol was often sold to the highest bidder and the chachomim had to tutor them on their duties on Yom Kippur. Entire masechtas are devoted to issues of Jewish merchants defrauding each other (short weights, borrowing first quality oil/fruits/wine and paying back with lower quality etc). I’ll provide the Middle Ages sources for you. As far as conversions went, I didn’t say they were unhappy Jews, just ignorant. Conversion was never a real option unless you brought something of value to the church. As a rule, people who converted were lost in no man’s land, no longer accepted by their families, but also not trusted by the church. The Inquision was designed for this. One of our misconceptions is that it persecuted Jews. It actually couldn’t care less about Jews; it went after converted Jews who they viewed as potential heretics.
There is a community living in Italy that converted en masse centuries ago that Catholics still refuse to intermarry with. Once the civil restrictions were removed and Jews could live in the cities, the removal of the shtetl peer pressure meant that the Jews by habit gave up their frumkeit. There were many anecdotal stories of Jews flinging there talleisim and tefillin into New York Harbor during the great waves of immigration of the late 19th and early 20th century .
So Zalman, other than Artscroll, what are your sources?