@Bernard
Interesting. I assume this was normal because nubian and sudanese were probably the majority of the population in egypt. They still left a functional civilization when they left, it just degraded over time due to the wars, droughts and the adoption of islam ofc.

What I think cool is that the powerful of civilization followed temperate climates after the ice age: first the middle east, then the meditarrean, central europe and finally britain/scandinavia. The migration of white men.