The Spanish Inquisition was a judicial institution established in 1478 by the Catholic Monarchs, Ferdinand II of Aragon and Isabella I of Castile. Its primary aim was to maintain Catholic orthodoxy in their kingdoms, particularly targeting converted Jews and Muslims suspected of secretly practicing their former religions. The Inquisition operated under the authority of the monarchy and the Pope, leading to trials, imprisonment, and executions. The Inquisition became notorious for its harsh methods, including torture and public executions. It played a significant role in the broader context of the Counter-Reformation, as it sought to strengthen the Catholic Church's influence and suppress dissent. The institution officially ended in the early 19th century.