Se considerarmos para definir o povo mais antigo o critério de civilização então os sumérios podem ser considerados a civilização mais antiga conhecia.
Inicialmente vejamos a definição de berço da civilização:
The cradle of civilization is a term referring to any of the possible locations for the emergence of civilization. It is usually applied to the Ancient Near Eastern Chalcolithic (Ubaid period, Naqada culture), especially in the Fertile Crescent (Levant and Mesopotamia), but also extended to sites in Armenia, and the Persian Plateau, besides other Asian cultures situated along large river valleys, notably the Indus River in the Indian Subcontinent and the Yellow River in China.
Civilization is usually taken to presuppose the presence of agriculture and urban settlements, and as such is a consequence of the Neolithic Revolution. This postulates that there is no single "cradle", but several independent developments of civilization, of which the Near Eastern Neolithic was the first. The extent to which there was significant influence between the early civilizations in the Fertile Crescent and East Asia is disputed, while the civilizations of the Andes and Mesoamerica are accepted as having emerged independently from those in Eurasia. If writing is taken as a prerequisite for civilization, the earliest "cradle" is Sumer (Jemdet Nasr) followed by Early Dynastic Egypt.
E agora um pouco do que foi a Suméria:
The history of Sumer, taken to include the prehistoric Ubaid and Uruk periods, spans the 5th to 3rd millennia BC, ending with the downfall of the Third Dynasty of Ur around 2004 BC, followed by a transition period of Amorite states before the rise of Babylonia in the 18th century BC.