In this study, we will discover the duties of married life in Lettres of Two Brides, one of Honore de Balzac's novels. We will use the narratological theory of Genette to analyse the focalization, the variation of narrative time and the characters of principal personages in this novel. As we explore the conception and the responsibilities of Louise de Chaulieu and Renee de Maucombe, two main heroines in Lettres of Two Brides, we can also study the style and the thought of Balzac. We will also discover the impact of the social system, such as the Napoleonic Code, on the situation of marriage through this novel.