'Saint Bernard is a large, intelligent dog that became famous for rescuing lost travelers. The dog was developed during the 1600s by a group of monks in the monastery of St. Bernard, in the Alps of Switzerland. At that time, many people traveled in the Alps on foot. Some lost their way or became buried in sudden snowdrifts or snowstorms. The St. Bernard was trained to rescue such people. With its keen sense of smell, the dog could find people who were buried in the snow. After it had found the lost traveler, it called for help by barking.'
Quoted from The World Book Encyclopedia
S-Sn Volume 17