A converso was a Jew who converted to Catholicism in Spain or Portugal in the Iberian Peninsula, particularly during the 14th and 15th centuries, or one of his or her descendants forced to convert to Christianity during the Middle Ages.

Pedro Berruguete in
1475 .
The Catholic monarchs Ferdinand and Isabella expelled those remaining openly practising Jews by the Alhambra decree of 1492, following the Christian Reconquista (reconquest) of Spain. However, even a significant proportion of these remaining practising Jews chose to join the already large converso community rather than face exile.

in which appears kneeling behind King Ferdinand the Catholic, the Inquisitor General
Tomás de Torquemada , and the Inquisitor of Aragon
Pedro de Arbués kneeling behind the queen
Photo: anonymous –
http://www.museodelprado.es/

Burning of Jews in Portugal in 1497.

Those who continued to practice Judaism in secrecy were calledMarrnos. The term specifically refers to the charge of crypto-Judaism. Crypto-Judaism is the secret adherence to Judaism while publicly professing to be of another faith. The phenomenon is especially associated with renaissance Spain, following the Massacre of 1391 and the expulsion of the Jews in 1492.

Secret
Passover Seder in Spain at the time of the Inquisition .
History painting of the Russian-Jewish artist
Moshe Maimon ,
1893.