The Spanish Inquisition was a judicial system that was established in 1478 by Catholic Monarchs of Spain in medieval times, Ferdinand II of Aragon and Isabella I of Castile.
The main purpose of this institution of inquisition was the detection of heretics and the maintenance of orthodoxy, although various other political, economic, and religious purposes have been attributed to it.
The inquisition itself existed before that, during the 12th century France where it was established to deal with the growing sectarianism in society.
One of the fundamental causes of The Spanish Inquisition was the hatred that existed between the Jews and the Christians during medieval times, the prevalent anti-Semitism, as well as the fear of the large Moorish population in Spain.
The Spanish Inquisition began when a Dominican friar from Seville, Alonso de Hojeda, impressed upon Queen Isabella the importance of purging the kingdom from the menace of Crypto-Judaism as well remnants of the Moors among the Andalusian conversos people who had converted to Christianity from Judaism and Islam.
Thus the institution of the Inquisition was established for which the assent of Pope Sixtus IV was obtained after Ferdinand II pressurized him with the threat of withdrawing his forces at a time when the fear of Turks overrunning Rome was high.
The Papal bull came in November 1478 through which the Monarchs of Spain gained the authority to oversee the inquisition.
Tribunals were established to advance the work of the Spanish Inquisition. The first such tribunal was established in Seville and in 1481 six people were burned at the stake after the charges of heresy were proved against them.
Thenceforth, the Inquisition grew in the Kingdom of Castile and similar tribunals were established in various other cities including Cordoba, Segovia, Toledo, and others.
However, with the passage of time, the influence of the monarchy over the inquisition grew and despite a subsequent Papal bull prohibiting the extension of the Inquisition to Aragon, the influence of the judicial system continued to expand.
With the passage of time, The Spanish Inquisition came increasingly under the secular authority. In 1484, an attempt by Pope Innocent VII to allow appeals to Rome under Inquisition was blocked by Ferdinand who issued an order according to which the punishments of death and confiscation were decreed for anyone trying to make recourse to Rome without royal permission.
Thus the authority of the monarchy was fully established over the Spanish Inquisition. In Aragon, there was considerable resistance against Inquisition and revolts erupted in Teruel. However, the murder of the Inquisitor Pedro Arbues tilted the public opinion in favor of the Inquisition and the tribunals were established throughout Aragon.
As the institution of the Spanish Inquisition grew in influence, so did the persecution of the Jewish and Muslim populations who had previously been forced to convert to Christianity. The slightest pretext and vague testimonies were used to bring and prove charges against the accused.
In 1492, the Alhambra Decree was released according to which expulsion of the Jews from Spain began. Historical accounts have varied about the exact number of Jews who were expelled, varying between 300,000 and 800,000.
However, modern estimates placed the number of Jews who emigrated at 40,000. The regions where the Jews emigrated as a result of the decree were Portugal, the Ottoman Empire, and North America. Other than that, tens of thousands of Jews were also baptized, who chose this option as a practical alternative to avoid expulsion.
The intensity of the Spanish Inquisition against the Crypto-Jews decreased during the mid of the 16th century but picked up again by the end of the century.
Other than the Protestants and the false converts from Judaism, forced converts from Islam were also a target of the Spanish Inquisition. These converts were known as Moriscos, consisting mainly of the Moorish population of Spain. These Moriscos were mainly concentrated in the regions of Aragon, Valencia, and Granada.
In 1502, this segment of the population was forcibly converted to Christianity. However, just like the Jews, they were suspected of practicing their religion in secret.
At the initial stages of the Inquisition, they did not face the ferocity of the Inquisition as much as the Jews did, because a large number of them were under the jurisdiction of the nobility and such a move would have caused considerable economic damage.
However, after the Morisco Revolt of 1568-70, the Spanish Inquisition dawned upon the Moriscos with its full force. For instance, in the tribunal of Granada, 82% of those accused between 1560 and 1571 were Moriscos.
One of the most important aspects of the Spanish Inquisition was the censorship and burning of the books deemed heretical by the Church. It was a common practice to draw up a list of such books and burn them publicly.
Although the practice existed in Europe before the Inquisition, it became intensified during the Inquisition. The first index of heretical books was published in 1551 which was a reprinting of a previous index released by the University of Louvain in 1550.
Over the course of a century, multiple such indices were drawn up which included books of all types, although the main attention was focused on religious books. Works of many renowned authors appeared in these indices, including those of Ovid, Dante, Machiavelli, Thomas More, and others.
It was also not uncommon to prohibit the translations of the Bible and to imprison the writers who did that, as is clear from the imprisonment of Fray Luis de Leon who had translated the Song of Songs from Hebrew.
Other than heresy and sectarianism, various other serious charges were leveled during the Spanish Inquisition. For instance, trials related to witchcraft became increasingly common, although the witch-hunt in Spain had less ferocity compared to the same practice in certain other European countries such as Germany, Scotland, and France.
Other common charges were blasphemy which included outright blasphemy to simple objectionable statements against religious beliefs, bigamy which was an offense against morals and generally resulted in imprisonment of a few years, and sodomy.
The institution of the Spanish Inquisition continued with declining intensity until it was finally abolished by a Royal Decree of 15 July 1834 during the reign of Isabella II.