I know that catholic and orthodox christians both have their own heads of religion, the Pope and the Ecumenical Patriarch, and I am also led to believe that the followers of Islam have their own head of religion (but I am not sure about this); but I have seen that catholic heresies do not have a head of religion.
This has got me thinking, would it be possible to set up a heretical pope/partriarch of a heretical faith (e.g. the lollards) if your ruler follows the teachings? This would be very interesting, but I have little idea of how centralized these heresies were in real life (e.g. if they had a singular leader), so any thoughts about this would be very much appreciated!