Mont Lassois, site of great Celtic fortifications near Châtillon-sur-Seine in the Côte-d’Or département, France. The hill-fort of Vix, on Mt. Lassois, seems to have been the centre of widespread political authority and extensive trade relations, especially during the 6th century bc. The rich Celtic and Greek artifacts found there, as well as those from the nearby tumulus burials near the villages of Vix and Sainte-Colombe-sur-Seine, indicate a frequent interchange of trade and gifts not only among the Celts themselves but also between the Celts and the Greeks through the port of Massalia (now Marseille).