between or beyond existing settlements. Gradually, however, the popula-
tion of the region had been increasing to a level where that expansive
process was no longer possible. Farmers were reaching the limits of land
with arable potential on the verge of the Kalahari Desert in the northwest
and in the rugged mountains at the southern end of the highveld. Through-
out southeastern Africa, as the possibilities for further expansion dimin-
ished, competition for land and water supplies grew more acute.26
Changing climatic conditions exacerbated the crisis. Rainfall decreased
significantly throughout the region during the first three decades of the
nineteenth century, with an exceptionally severe drought between 1800
and 18°7,
followed by another between 1820
and 1823.27
The problem
was especially serious in the northern Nguni area. There, the terrain is
marked by steep hills and deep valleys, which create widely different en-
vironments within short distances, and it was necessary for people to move
their cattle seasonally from one type ofpasture to another. Asthe land filled
up, pastures began to deteriorate through overstocking and people began
to interfere with the customary movements of cattle. By the end of the