I can't for the life of me remember what these people were called but during the Middle Ages there were a select few within the Christian church who would become hermits of a sort, entombing themselves within a section of the church and posing as a guide/counsel to people who came to see them (through a hole in the wall). The person lived off whatever pilgrims fed them. Anyway, if memory serves they were typically women. It seems kind of freaky but imagine how mysterious such a person would be, someone who is forevermore part of the church walls itself! And I'm pretty sure they did their fair share of preaching to passersby.