Who Are The Crypto-Jews?
The secret adherence to Judaism while publicly professing to be of another faith is the way that Jews who were forcibly converted to Christianity, known as “conversos”, and some, later as crypto-Jews, managed to stay alive through centuries of persecution. The forced conversion and subsequent expulsion of Iberian Jews in the 15th century ended 1000 years of Jewish life and culture in the Iberian peninsula. Practically overnight, those who escaped fled to the far corners of the world, taking their traditions with them. They were doomed to remain hidden wherever the Church was strong.
Many of those who converted did so against their will, such as at a mass forced conversion that occurred across Spain in 1391. It is important to note that this meant that a large portion of Spain’s Jews were converted more than one hundred years prior to their Portuguese coreligionists. Some, but not all, continued to practice aspects of Judaism secretly, but it is difficult to quantify both the percentage and degree of these secret practices.
See David M. Gitlitz’s “Taxonomy of New-Christians” in his book, “Secrecy and Deceit” (82-90)