The Tribunal of the Holy Office of the Inquisition (Spanish: Tribunal del Santo Oficio de la Inquisición) was authorized by Pope Sixtus IV in 1478 and the first inquisitors, Miguel de Morillo and Juan de San Martín, were appointed by the future Catholic Monarchs, King Ferdinand II of Aragon and Queen Isabella I of Castile, in 1480. Although its stated aim was to maintain Christian orthodoxy, it became an effective instrument of state power by replacing the Medieval Inquisition, which was under Papal control.
Over the course of the Inquisition, the Inquisition prosecuted an estimated 150,000 people for various offences. Of these, an estimated 3,000–5,000 were turned over to the state for execution, particularly in the initial 50 years, mostly by burning at the stake. Other punishments included penance and public flogging, exile, enslavement on galleys, and prison terms ranging from several years to life imprisonment. According to Joseph Pérez an important aspect of many of these punishments was the profit motive confiscation of all the victims' property.
The Inquisition was originally intended primarily to identify heretics among those who converted from Judaism and Islam to Catholicism. The regulation of the faith of newly converted Catholics intensified following the royal decrees issued in 1492 and 1502 ordering Jews and Muslims to either convert to Catholicism, leave Castile or face death. Hundreds of thousands of forced conversions, torture and executions, the persecution of conversos and moriscos, and the mass expulsions of Jews and Muslims from Spain all followed. An estimated 40,000–100,000 Jews were expelled in 1492. Conversos were subjected to blood purity statutes (limpieza de sangre), which introduced racially-based discrimination and antisemitism, lasting into the 19th and 20th centuries.
The inquisition expanded to other domains under the Spanish Crown, including Southern Italy and the Americas, while also targeting those accused of alumbradismo, Protestantism, witchcraft, blasphemy, bigamy, sodomy, and Freemasonry. A notable feature was the auto-da-fe, where the accused were paraded, sentences read, and confessions made, after which the guilty were turned over to civil authorities for the execution of sentences.
Roman Emperor Constantine legalized Christianity in 313 with the Edict of Milan. Persecuted under previous emperors, the new religion persecuted heterodox beliefs, such as Arianism, Manichaeism, Gnosticism, Adamites, Donatists, Pelagians, and Priscillianists. In 380, Emperor Theodosius I established Nicene Christianity as the state church of the Roman Empire. It condemned other Christian creeds as heresies and approved their repression. In 438, under Emperor Theodosius II, Codex Theodosianus (Theodosian Code) provided for property confiscation and execution for heretics.
Following the conversion of Spain's Visigoth royal family to Catholicism in 587, the situation for Jews deteriorated as the monarchy and church aligned to consolidate the realm under the new religion. The Church's Councils of Toledo imposed restrictions, including prohibitions on intermarriage and holding office, culminating in King Sisebut's 613 decree demanding conversion or expulsion, which led many Jews to flee or convert. Despite brief periods of tolerance, subsequent rulers and church councils intensified persecution, banning all Jewish rites, forcing baptisms, seizing property, enslaving Jews (after accusations of conspiracy in 694), taking children away from Jewish parents, and imposing severe economic hardships. This oppression alienated the Jewish population, causing some to welcome the Muslim invasion in 711.
While Muslims in the Holy Land were the primary targets of the Crusades, other perceived enemies of Christianity soon became targets. In 1184 Pope Lucius III created the Episcopal Inquisition to combat Catharism in southern France. Heretics were to be handed over to secular authorities for punishment, have their property seized, and face excommunication. When this failed to stem the heresy, Pope Innocent III called forth the Albigensian Crusade. The Crusaders killed 200,000 to 1,000,000 Cathars, perpetrated massacres (e.g. at Béziers), and burned hundreds at the stake. It was the start of a centralization in the fight against heresy, The Dominican Order was established to preach against the heresy, later serving as inquisitor throughout Europe. In 1252 Pope Innocent IV issued the bull Ad extirpanda, authorizing inquisitors to use torture against heretics.
European Jews became targets, leading to massacres and expulsions. While papal bulls sought to shield Jews from violence, starting in the twelfth century papal bulls also prohibited Jews from holding public office, required them to wear distinctive badges, ordered the burning of the Talmud, limited their employment, confined Jews to ghettos, and expelled them from the Papal States, along with other restrictions aimed at subordinating Jews. In 1231 Pope Gregory IX expanded the Papal Inquisition to Aragon. Cathars, Jewish converts and others deemed heretics were targeted, with trials, imprisonments and executions. Books by Spanish friars attacked Jews and Muslims. In Castile the Church Synod of Zamora protested rights granted to Jews by the king. Calls for restrictions on Spanish Jews were made by Popes and Cortes (assemblies of the Church, nobles and cities). Some kings protected Jews, since they benefited from Jews' taxes, and Jews serving as courtiers and tax collectors. Others, like Alfonso X, Sancho IV and Henry II, restricted Jews and exploited anti-Jewish sentiment for political gain.
The Shepherds' Crusade of 1320, started to help reconquer Spain from the Muslims, instead killed hundreds of Jews in France and Spain. In 1328, mobs inflamed by the sermons of Franciscan preacher Pedro Olligoyen massacred several Jewish communities in Navarre. Years of virulent anti-Jewish preaching by Ferrand Martínez, Archdeacon of Ecija, climaxed in the massacres of 1391 when riots broke out in Seville, Barcelona, Valencia, Toledo, Mallorca and elsewhere, killing thousands of Jews. To save themselves, some fled, mainly to North Africa, while an estimated 100,000, or one half of all Spanish Jews, converted to Catholicism. Following anti-Jewish riots in 1435 in Mallorca, Papal Inquisitor Antonio Murta played a key role in forced conversions of local Jews. The converts were called conversos. While mostly poor or of modest means, some conversos became successful in government and commerce, drawing resentment. Conversos were also suspected of continuing to practice Judaism in secret. Periods of stress, food shortages, plague and inflation led to attacks on conversos—in 1449 in Toledo (conversos were tortured and burned alive there), in 1462 in Carmona, again in Toledo in 1467, etc. In Cordoba in 1473 mobs killed conversos, regardless of sex and age, burning and looting their homes.
Start of the Inquisition against Jewish conversos
During her stay in Seville between 1477 and 1478, Queen Isabella was convinced of the existence of Crypto-Judaism among Andalusian conversos. A report, produced by Pedro González de Mendoza, Archbishop of Seville, and by the Dominican Tomás de Torquemada, confessor to Ferdinand and Isabella, corroborated this assertion. The Catholic monarchs requested a papal bull to establish an inquisition in Spain. In 1478 Pope Sixtus IV granted the bull Exigit sincerae devotionis affectus, to deal with those who had been baptized, but "revert to the rites and customs of the Jews and to keep the dogmas and precepts of the Jewish superstition and perfidy. ... Not only do they themselves persist in their own blindness, but also some who are born of them and some who associate with them are poisoned by their perfidy." To "expel this perfidy", "to convert the infidels to the proper faith", and punish all those "guilty of such crimes along with their harborers and followers", the bull permitted the monarchs to select and appoint three bishops or priests to act as inquisitors.