Spanish Inquisition Established

In 1478, Pope Sixtus IV issued a papal bull authorizing Ferdinand II of Aragon and Isabella I of Castile to appoint inquisitors to investigate heresy within their kingdoms. Initially targeting conversos — Jews and Muslims who had converted to Christianity but were suspected of practicing their former faiths — the Tribunal of the Holy Office expanded across Spain over subsequent decades. The institution served both religious and political functions, consolidating royal authority alongside enforcing Catholic orthodoxy. It operated until its formal abolition in 1834.