The Spanish Inquisition was an ecclesiastical tribunal run by the Spanish monarchy and established to root out heretics and other individuals who threatened the status of the Roman Catholic Church in Spain. Founded in 1478, the Spanish Inquisition was not formally abolished until 1834, and it is one of the most infamous of the numerous inquisitions held in Europe. It is estimated that at least 2,000 people died under the Spanish Inquisition, and countless others were tortured, subjected to horrific physical punishments, and forced to surrender all of their property.
This period in Spanish History was preceded by a period in which Spain was remarkably religiously diverse. At one time, Christians, Muslims, and Jews lived relatively peacefully together in Spain, exchanging ideas and information and creating a rich and vibrant culture. When the Spanish monarchy began its Reconquest of Moorish-occupied areas of Spain, however, it saw this as a threat, and the monarchy worked to re-establish Catholicism as the dominant religion in Spain.
Monarchs Ferdinand II of Aragon and Isabella I of Castile established the Spanish Inquisition, setting up an inquisition which was run by the government, rather than by the Church, a rather shrewd political move. The precise motivations for the Spanish Inquisition are a bit unclear. Beyond the obvious desire to reassert Catholicism in Spain, the monarchs might have had more cynical motives, such as a desire to get their hands on the property of people convicted under the Inquisition, and a pressing need to reduce the political clout of so-called Conversos, people of Jewish and Muslim faith who converted to Christianity, often due to pressure or political reasons.
Whatever the reasoning behind the Spanish Inquisition, it was organized much like a formal papal Inquisition. Inquisitors would enter a town and make a formal announcement after religious services, inviting people to confess or denounce others. Once a group of confessed or denounced criminals was identified, they would be brought to trial in a tribunal format. One of the major flaws with the Spanish Inquisition from a legal point of view is that the accused were not given the identity of their accusers, and they were often kept ignorant of the charges as well, making it impossible to defend themselves. They were also obliged to testify, with a refusal to testify being taken as an admission of guilt.
Conversos, who were often suspected of not being real Christians, were special targets of the Spanish Inquisition, since the Inquisition could only formally try Christians. The Inquisition also tried people for suspected heresy and a variety of other crimes, many of which were only abstractly related to the Catholic faith. Torture was widespread among Inquisitorial tribunals, as was pressure to encourage citizens to denounce each other with a promise of immunity from investigation. If convicted, some people were offered the chance to reconcile with the Church, usually after enduring a grueling physical punishment and the loss of their property. Other convicted criminals were executed.