In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
Q: A group of people that believe in the religion of Christianity are called?, Context: He insisted that, since forgiveness was God's alone to grant, those who claimed that indulgences absolved buyers from all punishments and granted them salvation were in error. Christians, he said, must not slacken in following Christ on account of such false assurances.
A:
Christians