Old Christian (Spanish: cristiano viejo, Portuguese: cristão-velho, Catalan: cristià vell) was a social and law-effective category used in the Iberian Peninsula from the late 15th and early 16th century onwards, to distinguish Portuguese and Spanish people attested as having cleanliness of blood, known as Limpieza de sangre, from the populations categorized as New Christian.
It was believed that many New Christians were practicing their original religion in secret and large numbers were Crypto-Jews.
The term was thus introduced in order for "Old Christians" to distinguish themselves from the converts (conversos) and their descendants, who were seen as potential heretics and threats to Catholic orthodoxy.
[4] New Christians of Muslim heritage were referred to pejoratively as moriscos, meaning Moor-like.
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