The production of economic surplus, or “prosperity,” was fundamental to financing the rise of pristine civilizations. Yet, prosperity attracts predation, which discourages the investments required for civilization. To the extent that the economic footing of civilization creates existential security threats, civilization is paradoxical. We claim that, in addition to surplus production, civilizations require surplus protection, or “security.” Drawing from archaeology and history, we model the trade-offs facing a society on its path to civilization. We emphasize preinstitutional forces, especially the geographical environment, that shape growth and defense capabilities and derive the conditions under which these capabilities help escape the civilizational paradox. We provide qualitative illustration of the model by analyzing the rise of the first two civilizations, Sumer and Egypt.