How are we to understand the thousand years (roughly 500-1500) between the end of the second-wave era and the beginning of modern world history? Historians, frankly, have had some difficulty defining a distinct identity for this millennium, a problem reflected in the vague terms used to describe it: a postclassical era, a medieval or “middle” period between the ancient and the modern, or…an age of third-wave civilizations. At best, these terms indicate where this period falls in the larger frame of world history, but none of them are very descriptive.

In some areas, for example, wholly new but smaller civilizations arose where none had existed before. Along the East African coast, Swahili civilization emerged in a string of thirty or more city-states, very much engaged in the commercial life of the Indian Ocean basin. The kingdoms of Ghana, Mali, and Songhay, stimulated and sustained by long-distance trade across the Sahara, represented a new West African civilization. Throughout Asia the influence of China.