Saint Joan ends with an epilogue, in which a good number of the characters materialize in a dream and discuss Joan's legacy on earth. In it we learn how King Charles had Joan's name cleared twenty-five years after he let her be executed. Also, a guy shows up from the future (1920) to tell them all that the Church has recognized Joan as a saint. The ending is a big shift in tone for the play. We go from high tragedy to high comedy. We go from straightforward realism to not-so-straightforward surrealism. What gives, Shaw? Why would you do such a thing?
It turns out that a lot of people were asking that question when the play was first produced. So much so, that he felt the need to defend it in his preface. He writes, "It was necessary by hook or crook to shew the canonized Joan as well as the incinerated one" (source). Shaw felt that if he didn't address in some way the fact that Joan was later recognized as a saint, he hadn't really done the job of chronicling Joan's story. She was one of those rare people whose death had just as large an effect on the world as her life.
He also felt it was very important to express his opinion that, if Joan were to come back to life today, she would just be executed all over again. He makes this point pretty darn clear in the play's very last moments. The characters all praise Joan after they find out she's been canonized. She's like, "Awe shucks, does this mean I should come back to Earth as a living person?" Everybody's like, "Uhh, not so much," and they disappear. In the end, Joan is left alone in pool of light asking, "O God that madest this beautiful earth, when will it be ready to receive thy saints?" (E.170). Read it. Decide what you think. Is Shaw's epilogue heavy handed? Or is it the work of pure genius?