The scene we have so far surveyed has been somewhat monotonous. The differences between the various groups of prehistoric farmers are insignificant beside the overriding similarity of their mode of life, relatively isolated as they were and almost entirely self-sufficient in their small villages. But by the middle of the fourth millennium B.C. this picture changed, first in Mesopotamia and a little later in Egypt; and the change may be described in terms of archaeological evidence. In Mesopotamia we find a considerable increase in the size of settlements and buildings such as temples. For the first time we can properly speak of monumental architecture as a dominant feature of sizable cities. In Egypt, too, monumental architecture appeared; and in both countries writing was introduced, new techniques were mastered, and representational art—as distinct from the mainly decorative art of the preceding period—made its first appearance. It is important to realize that the change was not a quantitative one. If one stresses the increased food supply or the expansion of human skill and enterprise; or if one combines both elements by proclaiming irrigation a triumph of skill which produced abundance; even if one emphasizes the contrast between the circumscribed existence of the prehistoric villagers and the richer, more varied, and more complex life in the cities—one misses the point. All these quantitative evaluations lead to generalizations which obscure the very problem with which we are concerned. For a comparison between Egypt and Mesopotamia discloses, not only that writing, representational art, monumental architecture, and a new kind of political coherence were introduced in the two countries; it also reveals the striking fact that the purpose of their writing, the contents of their representations, the functions of their monumental buildings, and the structure of their new societies differed completely. What we observe is not merely the establishment of civilized life, but the emergence, concretely, of the distinctive “forms” of Egyptian and Mesopotamian civilization.