This article accompanies the fable
Women in Trousers


Donna Woolfolk Cross argues in Pope Joan: A Novel (below) that she was a woman named Johanna von Ingelheim.  On the non-fiction side, there is The Myth of Pope Joan by Alain Boureau (originally in French and now translated into English) which attacks the legend, and The Legend of Pope Joan: In Search of the Truth by Peter Stanford, which defends it.