Building on recent theory of fictionality as a rhetorical concept, this article examines fictionality in the history of the novel. It argues that the Danish eighteenth-century novel provides answers to the question of the origin of the novel. A smaller novel corpus than that of the English eighteenth-century novel enables a method which combines quantitative studies and close readings. By examining the prefaces to the eighteenth-century Danish novels and studying the Danish novel compared to the Volksbuch, I argue that the genre is formed by a reflexive use of fictionality. I show how the prefaces to the Danish novel in the eighteenth century discuss different types of truthfulness to introduce and explain an emerging notion of fictionality. I demonstrate that concerns with fictionality did not arise in the Volksbuch, which was the most popular literary genre of prose before the novel in Denmark. Accordingly, the reflections on fictionality appear as something new that belongs to the novel. The article compares these findings to the English eighteenth-century novel and discusses novel theorists, such as Michael McKeon, Gregory Currie, Catherine Gallagher, and Nicholas D. Paige. Finally, I argue that the novel is indeed a new reflexive fictional genre and that various conclusions based on the Danish novel may be generalized.