Engraving depicting the Spanish Inquisition. The Spanish Inquisition, formally, the Tribunal of the Holy Office of the Inquisition, was a tribunal established in 1478 by Catholic Monarchs Ferdinand II of Aragon and Isabella I of Castile. It was intended to maintain Catholic orthodoxy in their kingdoms, and to replace the medieval inquisition which was under papal control. The Inquisition worked in large part to ensure the orthodoxy of recent converts, especially Jews, Muslims and others. Spain, circa 1560. (Photo by Fotosearch/Getty Images).