Another class of kobold lives in underground places. Folklorists have proposed that the mine kobold derives from the beliefs of the ancient Germanic people. Scottish historical novelist Walter Scott has suggested that the Proto-Norse based the kobolds on the short-statured Finns, Lapps, and Latvians who fled their invasions and sought shelter in northern European caves and mountains. There they put their skills at smithing to work and, in the beliefs of the proto-Norse, came to be seen as supernatural beings. These beliefs spread, becoming the kobold, the Germanic gnome, the French goblin and the Scottish bogle. In contrast, Humorists William Edmonstoune Aytoun and Theodore Martin (writing as "Bon Gaultier") have proposed that the Norse themselves were the models for the mine kobold and similar creatures, such as dwarfs, goblins, and trolls; Norse miners and smiths "were small in their physical proportions, and usually had their stithies near the mouths of the mines among the hills." This gave rise to myths about small, subterranean creatures, and the stories spread across Europe "as extensively as the military migrations from the same places did".