the city was known as augustodurum in the roman empire. it means the "durum" (celtic word "duro-" 'door', 'gate', welsh ', breton ' 'door', 'gate') dedicated to augustus, roman emperor. the celtic word "duron", latinised as "durum", was probably used to translate the latin word "forum" (compare fréjus "forum julii", dedicated to julius (caesar)).