Answer:
Christianity was a fast-growing religion
Step-by-step explanation:
They were powerful because they possessed things most normal people didn't like the ability to read and write. They could manipulate what people think and do because they were able to "communicate with god," so people would believe what they said. Also Christianity was a religion forced on people and growing fast that means more people were under their control. And they could expel people out of church, which means they won't go to heaven, and that scared them because no one want's to burn.