This paper is a survey of the origins of the major world civilizations of Eurasia and northern Africa, covering the period up to about 1200 B.C. It will consider especially the technological, economic, and political factors that enabled large governmental structures to be created.
What all early empires appear to have in common is that they grew up in great river valleys. After the Paleolithic period, when humans subsisted by hunting and gathering their food and which lasted for some hundreds of thousands of years, there was a technological and social shift that caused or allowed people to settle down in villages, plant crops, and domesticate animals. This was once called the Agricultural Revolution, but McKay et al. cite the work of Jack Harlan on the point that this change came slowly and that people, at least in Egypt, had already known for a long time how to plant seeds and harvest the food thus grown.1
The question is what had changed to cause this change in human social behavior. The answer is not known, but it has been suggested that gradual changes in weather and climate caused by the passing of the final stages of the last Ice Age dried up formerly fertile territories (e.g., the Sahara) and forced the existing populations to find more efficient ways to grow food. The resulting need to tend crops more aggressively may have forced people to create permanent living structures, instead of nomadic tents.
The oldest civilizations appear to be those of the Sumerians and Egyptians. It is not really known whether they influenced each other at the beginnings of their development, but it is possible. The Sumerians apparently emigrated into the Tigris-Euphrates valley at some time before 3000 B.C. According to some linguists, their language may have been distantly related to the Ural-Altaic language group, which includes Japanese and Turkish. They settled in and developed the lower Tigris-Euphrates valley, and by about...