Okay, so, I'm probably completely off here, but from what I understand about it very southern Africa, that is, the area currently encompassed by the state of South Africa et. al., is comparably more mild in terms of environment than the rest of Subsaharan Africa. Not exactly Mediterranean in climate, but not full of deserts of jungles, either.
So, why wasn't there any wide-scale unification of the area by any empire? I know the Zulu got sort of close, but I was hoping to see a Mali or Ethiopia-like state before Europeans get there.
Is it possible? If not, what would make it possible?
EDIT: Okay, I understand there were complex states and empires in South Africa now.
The current problem is preserving one to the point that it can advance and consolidate so that it can resist at least immediate European encroachment.