 It became popular in the 17th century writings of some scholars from the Age of Enlightenment, and has been endorsed by thinkers like Montesquieu, Voltaire, Smith, and Hume, as well as Immanuel Kant.It has been discussed in their essays and literary works; for example Voltaire's poem "Le Mondain" (1736) has been described as endorsing the doux commerce theory.Out of those, Montesquieu has been argued to be the writer most responsible for the spread of this idea in his influential "Spirit of Laws" (1748), and the theory is sometimes described as "Montesquieu's doux commerce."