The true origin of the Newfoundland Dog is hidden in the mists of time. There are three theories; the first is that the Newfoundland Dog evolved from the now extinct Black Wolf, perhaps by crossings with Asiatic Mastiffs that have entered into North America from Asia. The second is that the breed developed by crossings of native wolves, and/or Indian dogs, and the dogs the Vikings did bring to Vinland (the Viking name on Newfoundland) about 1000 A.D. The third is that the Newfoundland Dog owe its existence to the mastiffs, sheepdogs and waterdogs brought to the new continent by the fifteenth and sixteenth century European explorers
All I know is that they are big, smelly, friendly, slobbery, lovely beasts.