In this article, the three centralized Inquisitions in the Renaissance and early modern period are compared: the Spanish Inquisition founded in 1478, the Portuguese Inquisition in 1536, and the reformed, papal-led Roman Inquisition from 1542. All were developed from localized medieval ecclesiastical inquisition systems.

The Spanish Inquisition (covering the by now united monarchies of Castile and Aragon), and the Portuguese Inquisition, while sanctioned by the papacy, became essentially departments of state, with limited subsequent papal influence. This article highlights some variations between the Iberian Inquisitions and the Roman one, namely in the way that they were run both centrally and locally; in the priorities of their pursuits of heresy; in their rigor and severity of punishments; and their overall impact on religion and society. The Iberian Inquisitions and rulers started with a main concern about Jews who had converted to Christianity and their possible Judaizing practices. Spain later worried about those who had converted from Islam. The concern about Judaizers periodically resurfaced, especially in Portugal and its colonies. The Roman Inquisition had fewer issues in this area, but had more complex concerns and investigations of theological heresies from northern Protestants, Anabaptists, Waldensians, and with Valdesians and other internal Italian reform campaigners. All tribunals from the later sixteenth century attempted to control, and teach, better Christian moral behavior, to eradicate “superstitious” or “magical” practices, and sexual malpractices. Well-trained inquisitors were mostly more skeptical about witchcraft accusations than judges in other legal courts. Torture by inquisitors was more prevalent, varied, and harsher in Iberia and the colonies like Portuguese Goa, than under the Roman Inquisition, and than under some episcopal and secular courts in these Catholic states, and in many Protestant jurisdictions. Execution rates have often been exaggerated in anti-Inquisition propaganda, ignoring the high rates thereof and the barbarity found in episcopal and secular courts (whether Catholic or Protestant). They were probably higher in mainland Iberia than Italy or colonial central and southern America. The impact of book censorship varied considerably between, but also within, the various Inquisition areas. Conflicts over who controlled censorship, and inefficiencies in control mechanisms have recently been stressed. The main cultural casualties were probably the vernacular translations of Bibles and biblical texts, and Hebrew books.