Explain a paragraph of why south people of sahara desert had little contact with the rest of the world

The people in the south Sahara were out in the middle of the desert, and away from trade routes or anything of much importance. The kingdoms of west Africa, were historically connected with Morocco and Egypt, and the people in the south Sahara didn't have  much of anything Egypt wanted once the region turned to desert. The peoples of the south were nomadic, and until recent times had no reason to try to contact the north, but rather feared it

The answer would be hard press.