Spain was unique among European nations. It had been invaded by the Muslim Moors in 711, and most of Iberia (the peninsula comprising Spain and Portugal) was under their control by 750. Christians and Jews then lived in Islamic Iberia as the second-class citizens known as dhimmis, a situation that became far worse in 1172 when fundamentalist Muslims known as Almohads largely took control and gave the dhimmis a choice between conversion and death, causing many of them to emigrate. By this time, however, the Christian effort to reclaim their lands, the reconquista, had been progressing, and it was mostly complete by the late medieval period. This didn’t mean Spain was united, however. Muslims still controlled Granada in the 15th century, and the Christians themselves were divided politically.
This began to change with the marriage of King Ferdinand II of Aragon and Queen Isabella I of Castile in October 1469. Being part of a marriage that initiated the unification of their two regions, the monarchs were no doubt intensely focused on eliminating division. Thus did they not only plan to complete the reconquista by retaking Granada, but they also resolved to eliminate internal religious division as well, believing it an impediment to political unity. This is where the conversos – Jews who had converted to Christianity – enter the picture. Suspicious that they were “Judaizing” (practicing Judaism secretly), the monarchs instituted the Spanish Inquisition in 1478. And the rest is history – albeit often the twisted variety.
In other words, unlike earlier Inquisitions, the Spanish Inquisition wasn’t a response to unjust adjudication of heresy accusations by secular authorities, but was animated by religious suspicion. Kamen claims that one reason for this was the conversos’ failure to assimilate, a phenomenon which he says Spain’s Muslim community exhibited as well. I would add that if you had been occupied wholly or in part by Muslims for 781 years, it’s entirely possible you might be just a tad paranoid about alien religious influence on your soil. And these feelings no doubt only intensified, as the Spanish government expelled the nation’s remaining Jews (not the conversos) in 1492 and its last Muslims in 1609. Again, however, while this might have been motivated by the same spirit that created the Spanish Inquisition, it was not the work of the tribunal.
Selwyn Duke, “The inquisition and iniquity: Burning heretics or history?” The New American (2013, Dec 23)