The final books of the Esprit des lois (1748), dedicated to the institutions of the French kingdom in medieval times, have until now been scarcely examined. According to Montesquieu, in order to understand modern institu- tions, it is essential to acquire a thorough knowledge of history. Knowledge of the Middle Ages is the only way to understand how power should be organized in modern European monarchies. The article focuses in particular on the history of French judicial procedures in relation to the changes occurring in the figure of the sovereign in the medieval period. In Montesquieu’s view, the transformations that took place in judicial procedures guaranteed the creation of a moderate monarchy characterized by a bal- anced distribution of powers. The Author claims that in his theory Montesquieu uses and re elaborates various political ideas drawn from medieval philosophers and jurists (such as Guillaume Durand’s Speculum iuris or Baldus’ commentary on the Libri feudorum), as well as from Jean Bodin’s Six livres de la République.
Keywords: Montesquieu, history of the French monarchy, political thought, judicial power, kingship