Final answer:
There is no record of an individual being executed for converting Cathars in 1252, but Pope Innocent IV did authorize the use of torture against suspected heretics as part of the Medieval Inquisition.
Step-by-step explanation:
No individual was executed for being an effective converter of Cathars in 1252. However, the historical context of that period revolves around the Medieval Inquisition established by Pope Gregory IX. In 1230s, to combat heretical groups, such as the Cathars and the Waldensians, the Inquisition was created. Pope Innocent IV later authorized the use of torture on suspected heretics in 1252, escalating the severity of the proceedings. While many were executed during the Inquisition, the question seems to be based on a misunderstanding of historical facts as there is no record of someone being executed specifically for converting Cathars that year.