“For the whole of the fourth millennium BC, [Mesopotamian] society continued to become more hierarchical, which enabled the politico-administrative system to govern a developing society. The hereditary elites who held the reins of power were at the center of a vast, centripetal network that administered the region and fundamentally depended on their statutory capacity to mobilize the community’s workforce. This energy reserve, governed by the size of the population, enabled them to undertake public works (irrigation, for example), build sumptuous buildings, organize foreign expeditions, and obtain craft products and agricultural surpluses. This, in turn, enabled them to satisfy their own needs, maintain their dependents, meet their obligations, trade, and in general assume all the burdens of their public and private duties. . . . It was the need to control all these activities that led to the invention of writing during the Late Uruk Period.”

—The Art and Architecture of Mesopotamia, by Giovanni Curatol, Jean-Daniel Forest, Nathalie Gallois, Carlo Lippolis, and Roberta Venco Ricciardi, 2007.