Pope Sixtus IV Authorizes the Spanish Inquisition
Ferdinand and Isabella get papal permission to investigate converted Jews suspected of secretly practicing their old faith, and the Tribunal of Castile begins burning people at the stake within two years
Quick facts
- Authorized by
- Pope Sixtus IV, 1478
- First Inquisitor General
- Tomas de Torquemada (appointed 1482)
- Target
- Conversos suspected of secretly practicing Judaism
- Method
- Torture, confession, public auto-da-fe, burning at the stake
What happened
In 1478, under the influence of the clergyman Tomas de Torquemada, Ferdinand and Isabella created the Tribunal of Castile to investigate heresy among conversos, Jews who had converted to Christianity. The monarchs feared that even trusted conversos secretly practiced Judaism, and Ferdinand saw an Inquisition as a way to fund Castile's planned crusade against Granada by seizing the wealth of anyone convicted of heresy. By 1480, Jews in Castile were forced into ghettos and the Inquisition expanded to Seville; in 1481 alone, 20,000 conversos confessed to heresy under threat, and by year's end hundreds had been burned at the stake in public events called autos-da-fe. In 1482, after conversos who fled to Rome complained, Pope Sixtus IV himself protested that the tribunal was too harsh and wrongly accusing people, but he was overruled and Torquemada was named Inquisitor General instead, given authority to establish courts across Spain.
Why it matters
Torture became systematic and routine for extracting confessions, and the Inquisition outlasted Torquemada's death in 1498 by centuries, becoming a permanent feature of Spanish religious and political life that reached into the American colonies. It set the template Ferdinand and Isabella would use fourteen years later against Spain's unconverted Jewish population entirely.
How we know
HISTORY.com's account of the Inquisition traces the 1478 tribunal's creation, Torquemada's role, the 1480s persecutions, and Pope Sixtus IV's failed attempt to rein it in, citing the historical record of trial numbers and public autos-da-fe.
Sources
- HISTORY.com. Inquisition · Reputable sourcehistory.com · The domain "history.com" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- HISTORY.com. Ferdinand of Aragon marries Isabella of Castile · Reputable sourcehistory.com · The domain "history.com" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
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