The Fellatahs, who, since the beginning of the nineteenth century, have been the dominators of the Nigritians in West Africa, used to carry on a merciless campaign against their subjects, destroying their homes and fields, and seizing women and children by the thousands to barter away to the West, or to send across the desert. Describing the effects of a Fellatah raid, Barth says: "The whole village, which only a few moments before had been the abode of comfort and happiness, was destroyed by fire and made desolate. Slaughtered men, with their limbs severed from their bodies, were lying about in all directions and made passers-by shudder with horror."[5] The slave traffic in the Sudan gave rise at a very early date to regular slave markets. The city of Jenne on the Niger was, in the middle ages, the greatest emporium in West Africa, far outshining Timbuktu. From the fifteenth century to the present time, the most celebrated slave markets have been Kuka, on Lake Chad, Timbuktu, capital of the Songhay empire, Kano, capital of the Haussa empire, and Katsena, capital of a district of the same name. Rohlfs found at the Kuka slave market, white haired old men and women, children suckling strange breasts, young girls and strong boys who had come from Bornu, Baghirmi, Haussa, Logun, Musgu, Waday and from lands still more distant.[6] The slaves were carried across the desert by two kinds of caravans. First, those composed of nomad tribes, which migrated periodically from north to south. During the winter the tribes would pasture their camels along the edges of the desert, but in the spring they would visit the cities in the oases to gather up a supply of dates and other desert products to sell in the north. They would then in the same season proceed north to the cultivated regions of the Atlas mountains and arrive there in the midst of the harvest, exchanging their southern commodities for grain, raw-wool, and a variety of European goods. At the end of the summer they would return to the south, arriving at the oases just as the dates were ripening. Here the grain, wool and other stuffs from the north would be exchanged for dates and manufactured articles of the desert. The same tribes which advanced from the oases of the desert to the north also descended towards the south, thus establishing intercourse between the Barbary States and Timbuktu. Many slaves picked up by these immigrating tribes were carried from one oasis to another until they were finally sold into the states bordering the Mediterranean.