This paper studies to what extent religion has been used to legitimize political power
throughout the world and how this matters for current institutions. Historically, some rulers have used religion to legitimize their power, while others relied on more democratic means. This tendency, termed divine legitimization, incentivized rulers to embed religion into institutions. We illustrate within a simple framework that the use of religion to legitimize power and the consequent institutionalization of religion may help explain why religion and religious institutions have persisted despite modernization. To test empirically, we combine data on pre-modern religious beliefs across 1265 ethnographic societies, various geographic data, and current data on the prevalence of religious laws in 176 countries. We provide evidence in support of divine legitimization and the resulting institutionalization of religion. For identification, we exploit exogenous variation in the incentives to employ
religion for power purposes. We further document that countries that relied on divine legitimization are more autocratic today and their populace more religious. These results contribute to our understanding of the persistence of religious as well as autocratic institutions.