This chapter examines how irrigation agriculture transformed human communities into large, interdependent societies that required new mechanisms for coordination, control, and meaning. As populations expanded beyond kin-based groups, households became specialized, creating unprecedented social interdependence and anonymity. To maintain order, emerging elites organized tribute collection, warfare, and governance, while linking their authority to divine ancestry and cosmic order. Religious and political power were initially fused, as seen with Mesopotamian temples and Egyptian pharaohs, but gradually differentiated into distinct institutions—church, government, and military—each reinforcing the social hierarchy. Priests evolved as full-time bureaucrats responsible for transmitting moral and doctrinal norms that stabilized these expanding systems. The chapter concludes by distinguishing institutions—the shared norms and behaviors guiding society—from organizations, which enact those norms through governance structures. Together, these developments mark a crucial shift toward enduring, self-perpetuating organizations capable of shaping human behavior and belief far beyond individual lifespans.