The Inquisition was an office within the Catholic Church that dealt with matters of religious orthodoxy (proper belief and practice), and the Spanish Inquisition’s reputation is not simply a result of its activities, but also of propaganda wars of the sixteenth century and later. As Spain increasingly portrayed itself as a champion of Catholicism and acquired a global empire, Protestant powers in northern Europe, particularly England and the Netherlands, found themselves both opposed to its empire building and its religious stance. Put crudely, the activities of the Inquisition were portrayed in as negative a light as possible to beat Spain and Spanish interests in general. But what was actually happening in Spain?
At that time, Spain was not a single country per se. The two main powers in late medieval/Renaissance Spain were the Crown of Aragon in the east (which ruled over the area that is now known as Aragon, Catalonia, Valencia, and much of southern Italy), and Castile which dominated much of the rest of what we now know as Spain (the most notable exception being the small kingdom of Navarra in the northeast). Neither were actually fond of the Inquisition. Inquisitors were not answerable to the bishops in whose diocese they operated, and their independence irked the kings of Aragon, who did their best to prevent it functioning effectively in their realm. Meanwhile, the rulers of Castile simply did not allow it to be established in their territory at all.
A change occurred upon the marriage of King Fernando of Aragon to Queen Isabella of Castile in 1469, a dynastic union of the two crowns that eventually resulted in the creation of modern Spain. Fernando and Isabella have left a large legacy along the Camino (Isabella performed the pilgrimage to pray for help conceiving) and indeed the world (they sponsored Christopher Columbus’ first voyages in 1492). Pope Sixtus IV granted Los Reyes Católicos (the Catholic Monarchs, as they became known), the right to appoint inquisitors answerable to them and not local bishops or Rome, and so the Inquisition began to gain a foothold.
Mostly the Inquisition focused upon Conversos i.e. Jews and Muslims who had been compelled to convert to Christianity to avoid expulsion, but who were never subsequently trusted and viewed as converts of convenience or even heretics. Protestantism was almost non-existent in Spain and witchcraft was a minor concern/not really taken seriously; most Spanish Inquisition witchcraft trials ended in acquittal (indeed Spain was one of the safest places to be tried for witchcraft; much safer than Britain or Germany). Overall, the numbers executed by the Spanish Inquisition (or rather by secular powers on behalf of the Inquisition) were low. While very difficult to quantify, maybe 2000 people were executed up to the middle of the sixteenth century, when numbers began to tail off substantially. By describing this as ‘low’, I don’t intend to belittle their lives and deaths, but simply to suggest that the popular reputation of the Spanish Inquisition would induce us to imagine a much higher number. Professor Alec Ryrie (Durham University), in his wonderful Gresham Lecture The Spanish Inquisition: Spain’s ‘Black Legend’ (which I highly recommend watching, here), points out by comparison that approximately 1,500 people have been executed by authorities in the United States since the 1970s.