After the death of Gregory IX, who established the Inquisition, the succeeding pontiffs tightened and kept a close surveillance on the proceedings but did not radically change the original tribunal. The Inquisitors themselves, responding to criticisms of their methods of procedure, submitted a number of questions to the bishops assembled at the Council of Narbonne, 1243-1244, which was presided over by the legate of Innocent IV. At this Council, and at several others within the next few years, the inquisitorial process was set forth in minute detail:
- an Inquisitor must operate only in his own assigned district
- no one is to be convicted without sufficient proof of his own confession: “It is better for the guilty to remain unpunished than for the innocent to be punished.”…
- the names of witnesses are not to be published (however the accused is entitled to list the name of his enemies, who then cannot be permitted to testify against him).
- the Inquisitor is to see to it that the accused is provided adequate means to defend himself.
- witnesses are to be protected
- those who wish to repent are to be absolved and given only light penances
- if lacking, prisons are to be built
- the relapsed or the recalcitrant are to be abandoned to the secular arm…
With the election of Innocent IV (1243-1254), a canon lawyer, a determined effort was made to organize the above mentioned prescriptions and various papal directives into an ordered procedure…Pope Innocent IV made it his policy to check the spread of heresy but at the same time to restrain exaggerated persecutions.
Albert Shannon, The Medieval Inquisition (1991)