Pope Innocent IV issues the papal bull ad extirpanda, which authorizes, but also limits, the torture of heretics in the Medieval Inquisition.

Pope Innocent IV, born Sinibaldo Fieschi, was head of the Catholic Church and ruler of the Papal States from 25 June 1243 to his death in 1254.

A papal bull is a type of public decree, letters patent, or charter issued by the pope of the Catholic Church. It is named after the leaden seal (bulla) traditionally appended to authenticate it.

Ad extirpanda was a papal bull promulgated on Wednesday, May 15, 1252 by Pope Innocent IV which authorized under defined circumstances the use of torture by the Inquisition as a tool for interrogation.

Heresy in Christianity denotes the formal denial or doubt of a core doctrine of the Christian faith as defined by one or more of the Christian churches.

The Medieval Inquisition was a series of Inquisitions from around 1184, including the Episcopal Inquisition (1184–1230s) and later the Papal Inquisition (1230s). The Medieval Inquisition was established in response to movements considered apostate or heretical to Roman Catholicism, in particular Catharism and Waldensians in Southern France and Northern Italy. These were the first of many inquisitions that would follow.