Abstract

Caesar writes among the main preoccupations of the Druids “the measurement of the world and of territories”. A simple surveying being excluded, other methods have to be considered, and first the spotting of privileged directions from high points (such as the Puy-de-Dôme, the Montagne de Dun, the Mont Dardon, the hill of Sion-Vaudémont…) allowing a kind of primitive triangulation. It has been noticed that in the obtained patterns, the places known as Mediolanum play a major role. Thus Milano, Mediolanum of the Insubri and Châteaumeillant, home of the Biturigi, can be connected by a straight line across the Mont Blanc and the Montagne de Dun, this last one being the center of several equidistances leading to Meilhan-sur-Garonne, Saintes, Évreux, all of them ancient Mediolanum. Geometrical relations, not less striking, link among others, the Mediolanum de Samoreau (landmark on the bank of the Seine) to Maulain (Haute-Marne), Mâlain (Côte‑d’Or) and Moliens (Oise). Consistant with the Celtic tradition, the sacralization of the central points adds up to a real endeavour of Gallic geodesy, the chronology of which should be elaborated.