Moriscos were former Muslims and their descendants whom the Catholic Church and Habsburg Spain commanded to forcibly convert to Christianity or face compulsory exile after Spain outlawed Islam. Spain had a sizeable Muslim population, the mudéjars, in the early 16th century.

Forced conversion is the adoption of a religion or irreligion under duress. Someone who has been forced to convert to a different religion or irreligion may continue, covertly, to adhere to the beliefs and practices which were originally held, while outwardly behaving as a convert. Crypto-Jews, Crypto-Christians, Crypto-Muslims and Crypto-Pagans are historical examples of the latter.