Gordon Childe defined the development of civilization as the result of two successive revolutions: the Neolithic Revolution, triggering the development of settled communities, and the Urban Revolution, which enhanced tendencies towards dense settlements, specialized occupational groups, social classes, exploitation of surpluses, monumental public buildings and writing.Few of those conditions, however, are unchallenged by the records: dense settlements were not attested in Egypt's Old Kingdom and were absent in the Maya area; the Incas lacked writing altogether; and often monumental architecture preceded any indication of village settlement.
The phrase "cradle of civilization" plays a certain role in national mysticism.
have attributed these settlements to migrants from the Fertile Crescent in the Near East returning during the Egyptian and North African Neolithic, bringing agriculture to the region.
Eridu is the oldest Sumerian site settled during this period, around 5300 BC, and the city of Ur also first dates to the end of this period.
Historic times are marked apart from prehistoric times when "records of the past begin to be kept for the benefit of future generations"; which may be in written or oral form.
If the rise of civilization is taken to coincide with the development of writing out of proto-writing, the Near Eastern Chalcolithic, the transitional period between the Neolithic and the Bronze Age during the 4th millennium BC, and the development of proto-writing in Harappa in the Indus Valley of South Asia around 3300 BC are the earliest incidences, followed by Chinese proto-writing evolving into the oracle bone script, and again by the emergence of Mesoamerican writing systems from about 900 BC.