The Inquisitions were judicial institutions or tribunals that were established by the Roman Catholic Church in order to seek out, try, and sentence people that the Roman Catholic Church believed to be guilty of heresy. The purpose of the inquisitions was to secure and maintain religious and doctrinal unity in the Roman Catholic Church and throughout the Holy Roman Empire, through either the conversion or persecution of alleged heretics. Historians generally distinguish the Inquisitions based on four different time frames and areas that they took place in. These are the Medieval or Episcopal Inquisition, the Spanish Inquisition, the Portuguese Inquisition, and the Roman Inquisition.