From about the middle of the eighteenth century, events in southern Africa developed in such a way as to strengthen the hand of the chiefs. Overpopulation made prime ecological locations harder to find. Competition for resources became sharper, and commoners were more willing to subject themselves to those chiefs best able to guarantee their subsistence. Furthermore, the new products traded at Delagoa Bay after 1750 furnished the chiefs with new means of patronage and incentives to expand their territory. These pressures were particularly acute in what is today northern KwaZulu-Natal, leading ultimately to the rise of the Zulu kingdom under Shaka and a period of dispersion known as the Difaqane or Mfecane (see The Mfecane).