Medieval Inquisition

The Medieval Inquisition was a series of Inquisitions (Catholic Church bodies charged with suppressing heresy). In 1231, Pope Gregory IX initiated the Medieval Inquistion by appointing a number of Papal Inquisitors, mostly Dominicans and Franciscans, to bring order to the process of dealing with heresy and prevent mob justice.

Reference

 * Assassin's Creed movie - Family Tree DNA