This is a very ancient breed of the mastiff type that came across the Alps with the Roman conquerors. The St. Bernard was bred around the year 1,000 by St Bernard Monks that founded a refuge for travelers crossing the dangerous alpine passes between Switzerland and Italy.
It was observed that the dogs at the St. Bernard monastery had an unusual ability to sense about impending danger from storms and avalanches.
The outstanding sense of smell of the St Bernard enables him to scent a person buried in as much as 3 meters of snow.