Lope's two plays El mayordomo de la duquesa de Amalfi and El perro del hortelano are very similar in plot, structure and spatial background. Nevertheless, the former is a tragedy and the latter is a comedy, with three major specific factors that made this distinction possible. The first is the fatal mistake of Libia, the servant of El Mayordomo de la duquesa de Amalfi, and the wit of Tristán, the servant of El perro del hortelano. The second is the absolute destiny. For Antonio, the main character of El mayordomo de la duquesa de Amalfi, love with the hostess is the absolute destiny, but for Teodoro, the protagonist of El perro del hortelano, love is not the absolute destiny. Third is the attitude of the heroine. Camila, the heroine of El Mayordomo de la duquesa de Amalfi, refused to change, but Diana, the heroine of El perro del hortelano, accepted the change and led the change. In conclusion, the play becomes a comedy or a tragedy, depending on whether one views the love between a man and a woman of different social standing in a progressive or conservative way.