"The population count of Egypt under the first dynasties was possibly between 1 and 2 million inhabitants, rising slowly until the end of the Old Kingdom when a century of low Nile floods and the decay of the central power with its role of hoarding and redistributing grain surpluses caused famines which killed many of the very young and the old." The peak, or golden age, was considered to be the fourth dynasty. Source: http://www.reshafim.org.il/ad/egypt/people/