In Egypt at the beginning of the fourth millennium BCE two distinct cultural units developed. In the south arose the Naqada culture, named after the great cemetery discovered by Petrie at the end of the nineteenth century. In the north, spanning the Delta up to the Memphite region, arose the “Maadi-Buto,” or Lower Egyptian culture, named after the two reference sites of Maadi and Buto. The establishment of these two entities, whose material culture and funereal traditions differed, was the result of the role played in the process of neolithization of the Nile Valley by two great regions: the East on the one hand and the Sahara on the other. During the fourth millennium, after a period of interactions between those two regions, a cultural uniformity was born comprising elements of a mixed culture dominated by southern features.