On April 13, 1556, Portuguese Marranos who reverted back to Judaism were burned by order of the Pope. From the article:
"Conversos and Marranos
The terms “Marrano” and “converso” were applied in Spain and Portugal to the descendants of baptized Jews suspected of secret adherence to Judaism. Converso, from the Latin conversus, meant literally the converted. Various origins for the term “marrano” have been suggested, which include the Hebrew marit ayin (“the appearance of the eye”), referring to the fact that the Marranos were ostensibly Christian but actually Jews; mohoram attah (“you are excommunicated”); the Aramaic-Hebrew Mar Anus (“forced convert”); the Hebrew mumar (“apostate”) with the Spanish ending ano; the Arabic mura’in (“hypocrite”); and the second word of the ecclesiastical imprecation anathema maranatha. All such derivations, however, are unlikely. The most probable is from the Spanish word meaning swine or pig, derived from the Latin verres “wild boar.” The term probably did not originally refer to the Jews’ reluctance to eat pork, as some scholars hold; from its earliest use, it was intended to impart the sense of loathing conveyed by the word. Although romanticized and regarded by later Jewry as a badge of honor, the term was not as widely used, especially in official circles, as is often believed. In Latin America, as a rule, it is not found in official documents, and there is little evidence of its unofficial use in most places. It is not clear if the “Old Christians” only, or the secretly practicing Jews, also called themselves “marrano.”