What is christianity really? Constantine converted the masses to christianity. Did he say one religion was christian and not the other? No. other christian religions were founded. It\'s hard to say which religion is christian and which isn\'t because people all have their idea of what christian is. Just because the mormon religion doesn\'t live to the code of other christian religions doesn\'t make them not christian. They are as much christian as their neighbors. They just have different beliefs and doctrines from other churches.