Places where the Alps were crossed are called passes, and are points at which the alpine chain sinks to form depressions, up to which deep-cut valleys lead from the plains & hilly pre-mountainous zones. The oldest names for such passes are Mont (still retained in cases of Mont Cenis and Monte Moro), for it was many ages before this term was applied to mountains themselves, which with a few very rare exceptions (e.g. Monte Viso was known to the Romans as Vesulus) were for a long time disregarded.