Thus far we have noted the role of physiographic factors that have led to building the nuclei of empires and civilizations.  They have been parallelled by social factors as men took advantage of natural opportunities to concentrate, feed and house ever larger human aggregates.

Empires and civilizations have been built up by comparatively large numbers of human beings concentrated in relatively small spaces.  Wandering food gatherers and herdsmen ranged widely in search of game and grass.  Cultivators settled in villages from which they could work the land.  If crops were scanty, population was sparse.  Only abundant crops, dependable, season after season, provided the basis for large settled populations.

Large, settled populations, adequately supplied with the essentials of life, enabled human beings to organize social centers in which a comparatively few people, tending their animals and working the land, could release a comparatively large part of the population to devote its time and energy to trade and commerce, to industry and transport, to the arts and sciences and to the organization, direction and administration of large scale enterprises such as government, the military, construction and the mobilization of sufficient labor power to carry on and enlarge their enterprises.  In its simplest essence this was politics.

Egyptian government, in its broad sense, rested on a class structured society:  the aristocracy, the priesthood, officialdom, businessmen, highly trained scientists and engineers, skilled craftsmen and an immense proletariat consisting of tenant farmers, peons, slaves and war captives.

At the top of the political structure was an absolute monarch who wielded power that was limited only by the ambition, tolerance and loyalty of his associates—­nobles, priests, soldiers, businessmen and political advisers, and by the willingness of the rural and urban masses to work and fight for their overlords.  A number of the monarchs (Pharaohs) ruled for long periods—­up to sixty years.  It was during these long reigns that the Egyptian Kingdom was organized, strengthened and unified, the rule of the monarch was safeguarded; ambitious nobles were placated or destroyed; and the leadership succession was determined and assured.

The nucleus of the Egyptian Empire was a dictatorship by a self-perpetuated elite, headed by lords spiritual and temporal.  Both groups held land, accumulated wealth and exercised authority.  It was a government combining the theory of absolutism with the practice of public responsibility.  It was sufficiently arbitrary to get things done.  It was sufficiently inclusive to recognize and utilize special ability.  It was sufficiently structured to carry on from dynasty to dynasty.  It was sufficiently flexible to consolidate scattered communities into the Old Kingdom, to unite Lower and Upper Egypt, to extend its authority into Central Africa, the Near and Middle East and parts of Eastern Europe, thus laying the foundations for history’s most extensive and long-lasting civilization during the period 3500 to 500 B.C.