From the Stone Age to Mesopotamian Civilization, 400,000–1000 B.C.E.

People in the Stone Age developed patterns of life that still exist. The most significant of those early developments were (1) the evolution of hierarchy in society and (2) the invention of agriculture and the domestication of animals. Those inventions allowed people to stay in one place and raise their own food instead of wandering around to find things to eat in the wild. This change in how human beings met their most basic need—nutrition—led them to settle down in permanent communities for the first time. Eventually, some of these communities grew large enough in population and area to be considered cities. The conditions of life in these populous settlements incubated civilization, beginning in the fertile plains of the two great rivers of the Near East, the Euphrates and the Tigris. There, the Mesopotamians learned to work metals, and their rulers’ desire to acquire and control the sources of these increasingly precious resources generated the drive to create empires. That drive in turn set the world on a course that extends to the modern age.