This essay considers David Rudrum's claim that narrative is a type of language act that needs to be construed with regard to its use. Here this claim is related to one of the most influential literary traditions in the history of fiction: the Eastern Book of Sindibad and its Western offshoot, the Seven Sages of Rome, in which narrative use is of central significance. I focus more particularly on a tale embedded in the Eastern Book of Sindibad, "The Merchant and the Rogues," which was adapted and translated into Middle English in the form of the fifteenth-century Tale of Beryn, an anonymous continuation of Chaucer's Canterbury Tales. The Sindibad tale and the Tale of Beryn thematize narrative use in the context of a trial, in which the pleas and counterpleas highlight the function of fictionalizing acts. Fiction in these narratives is conceptualized as a practice. Finally, I argue that the production and reception of the Tale of Beryn must be linked to the socioprofessional milieu and cultural activities of late medieval law students.