Crypto-Judaism

Crypto-Judaism is the secret adherence to Judaism while publicly professing to be of another faith; practitioners are referred to as "crypto-Jews" (origin from Greek kryptos – κρυπτός, 'hidden').

The term is especially applied historically to Spanish and Portuguese Jews who outwardly professed Catholicism, also known as Conversos, Marranos, or the Anusim. The phenomenon is especially associated with medieval Spain, following the Massacre of 1391 and the expulsion of the Jews in 1492. After 1492 in Spain and 1497 in Portugal, officially they no longer existed. The Spanish Inquisition and the Portuguese Inquisition were established to monitor converted Jews and their descendants for their continued adherence to Christian faith and practice, with severe penalties for those convicted of secretly continuing to practice Judaism. Information about secretly observant Jews largely survives in Inquisition cases against individuals.