The White Crown and the Horus falcon appear first on a Nubian burner

The elites of Qustul and their counterparts in the Naqada communities of southern Egypt built the visual language of pharaonic rule together, across the second half of the fourth millennium BCE. The Qustul finds include serekhs, the panelled palace facades that later frame a king's name, and sacred boats. The best studied piece is an incense burner carved with a procession of three such boats moving toward a serekh. The first boat carries a bound prisoner with a guard standing behind him holding a mace. The second carries the ruler, wearing the White Crown that later stands for Upper Egypt, with the Horus falcon in front of him. In the third stands a feline figure with a falcon behind it, marking the feline as a god. Every element there becomes standard in Egyptian royal art. All of them sit on an object from a Nubian tomb that predates unification. The crown the pharaohs wore had been worn at Qustul first.

Around the thirty-fourth century BCE the climate of the eastern Sahara turned sharply drier and stayed that way. Steppe and semidesert grassland that had carried herds for millennia became the desert it is now, though patches held on well enough to support marginal livestock raising as late as about 2000 BCE. The pastoralists living out there had to go somewhere. They moved out of the emerging desert and settled among the communities already living along the Nile. That is the event that produced the Egypt of the textbooks, the thin green ribbon dependent on an annual flood. Before it, this was open country with mobile herders and a river running through it. After it, thousands of people and their cattle were compressed onto a floodplain a few kilometres wide. The competition for land and the density of population that followed drove polities to grow and swallow one another until the whole valley was unified around 3100 BCE.