The hypothesis is regarded as a fringe theory. Mainstream scholars reject the notion that Egypt was a black (or white) civilization; they maintain that, despite the phenotypic diversity of Ancient and present day Egyptians, applying modern notions of black or white races to ancient Egypt is anachronistic.[10][11][12] In addition, scholars reject the notion, implicit in the black Egypt hypothesis, that Ancient Egypt was racially homogeneous; instead, skin color varied between the peoples of Lower Egypt, Upper Egypt, and Nubia, who in various eras rose to power in Ancient Egypt.