Another factor has added to the impetus of Hyborian drift. A tribe of that race has discovered the use of stone in building, and the first Hyborian kingdom has come into being--the rude and barbaric kingdom of Hyperborea, which had its beginning in a crude fortress of boulders heaped to repel tribal attack. The people of this tribe soon abandoned their horse-hide tents for stone houses, crudely but mightily built, and thus protected, they grew strong. There are few more dramatic events in history than the rise of the rude, fierce kingdom of Hyperborea, whose people turned abruptly from their nomadic life to rear dwellings of naked stone, surrounded by cyclopean walls--a race scarcely emerged from the polished stone age, who had by a freak of chance, learned the first rude principles of architecture. The rise of this kingdom drove forth many other tribes, for, defeated in the war, or refusing to become tributary to their castle-dwelling kinsmen, many clans set forth on long treks that took them halfway around the world. And already the more northern tribes are beginning to be harried by gigantic blond savages, not much more advanced than ape-men. The tale of the next thousand years is the tale of the rise of the Hyborians, whose warlike tribes dominate the western world. Rude kingdoms are taking shape. The tawny-haired invaders have encountered the Picts, driving them into the barren lands of the west. To the northwest, the descendants of the Atlanteans, climbing unaided from apedom into primitive savagery, have not yet met the conquerors. Far to the east the Lemurians are evolving a strange semi-civilization of their own. To the south the Hyborians have founded the kingdom of Koth, on the borders of those pastoral countries known as the Lands of Shem, and the savages of those lands, partly through contact with the Hyborians, partly through contact with the Stygians who have ravaged them for centuries, are emerging from barbarism. The blond savages of the far north have grown in power and numbers so that the northern Hyborian tribes move southward, driving their kindred clans before them. The ancient kingdom of Hyperborea is overthrown by one of these northern tribes, which, however, retains the old name. Southeast of Hyperborea a kingdom of the Zhemri has come into being, under the name of Zamora. To the southwest, a tribe of Picts have invaded the fertile valley of Zingg, conquered the agricultural people there, and settled among them. This mixed race was in turn conquered later by a roving tribe of Hybori, and from these mingled elements came the kingdom of Zingara.