as told to me by a priest
If you look at the priest’s emma, you notice its sort of flat and has a small ridge around it. Whereas that of a bishop is nice and rounded. Originally the priest’s emma was nice and round like the bishop’s but through years of pressure from the hierarchy from above and from the congregation from below has smashed the priest’s emma flat and raised the ridge around the edge. The reason the bishop’s is still round despite potential pressure from below by the congregation there is no pressure from above because the only one above bishops is God and He is compassionate.