While Martin Luther doesn’t appear as a character in Wolf Hall, his books and ideas are often discussed. He was a German theologian who questioned some ideas of the Catholic Church and whose writings led to the division of Western Christianity into Catholicism and Protestantism. His books are considered heretical in England during Henry’s reign and anyone who is caught reading them is arrested and executed by Thomas More. While Cromwell doesn’t agree with all of Luther’s ideas, he is interested in knowing what they are, which is why he smuggles the books into England and reads them. Cromwell even shares Luther’s ideas with Wolsey.