In his Voyage à Bourg-Saint-Andéol (1886), Albin Mazon laments the sad state of the antique Mithras bas-relief near the sources of the Tourne (Ardèche). Its once idyllic enclosure has been destroyed by the construction of a rail road and the relief itself has become indecipherable. Mazon's Voyage presents a provincial historiography in which narratives, lexicographic and semantic divagations and museal interests join in an endeavour to decipher the past as a lexis that had become increasingly incomprehensible in the changing cultural and socio-economical landscape of modernity. Indecipherability and the railroad, enclosure versus expanding networks of mobility went side by side. Mazon's Voyage figures as a primary source in Frederic Mistral's Poème du Rhône (1896). With Mistral, the Mithras bas-relief becomes however decipherable in various ways. It will be argued, against the background of Mistral's anti-modern recuperation of the past, his ideal of a premodern, rural domesticity versus the new, abstract citoyenneté, and his topological and lexicographic interests, how this recuperation relates with elements, in the Poème, of an anti-modern past that constitutes an eschatological promise for the future and symbolises "la dilection unique et primitive/ d'un monde neuf et brillant de jeunesse!"