Paul continued to work on plays and novels and his career waxed and waned over the years. One of his best known novels was his 1915 bestseller titled "Die Tänzerin Barberina" (Barberina, the dancer) whose main character was based on the dramatic life of Italian dancer Barbara Campanini (1721–1799), who was brought to Berlin by Frederick the Great of Prussia to become a highly paid dancer at the newly opened Berlin Opera and his lover. Literature critics considered Paul's psychological portrayals of Voltaire in "Ormen i paradiset" and Napoleon in "S:t Helena" among his literary highlights.