This paper analyses some of the emendations that Lope made in the autograph manuscript of the comedy La buena guarda , kept in the funds of the National Library of Spain, and specifically those that relate to two names: Guzmán and Montalvo. The study of them, as well as the purpose for which Lope reviewed the comedy show that corrections of these names are intended to remove two literary sources of comedy: the second apocryphal part of Guzmán de Alfarache and the Corónica del Orden del Cister of Bernabé de Montalvo.