What is the theme in Pope Joan by Donna Cross?

Knowledge over superstition are the main themes in the story. Joan's early ability to reason through problems and questions reflects the dawning of a new age. She is not willing to settle for the accepted stories which people concoct to try to explain their world, but chooses to look underneath for the real truth. The author presents the Dark Ages as a time during which people locked themselves into a fearful belief system so rigid that it prevented them from looking beyond it.