By the eighth millennium BC, people of a Neolithic culture had settled into a sedentary way of life there in fortified mudbrick villages, where they supplemented hunting and fishing on the Nile with grain gathering and cattle herding. Neolithic peoples created cemeteries such as R12. During the fifth millennium BC, migrations from the drying Sahara brought neolithic people into the Nile Valley along with agriculture. The population that resulted from this cultural and genetic mixing developed a social hierarchy over the next centuries which became the Kingdom of Kush (with the capital at Kerma) at 1700 BC. Anthropological and archaeological research indicate that during the predynastic period Nubia and Nagadan Upper Egypt were ethnically, and culturally nearly identical, and thus, simultaneously evolved systems of pharaonic kingship by 3300 BC.