Caesaropapism

Caesaropapism is a political arrangement in which a ruler exercises substantial authority over religious institutions, including their leadership, doctrine, or administration.

Erastianism: The doctrine that the state should control or regulate the church, especially in its institutional affairs. It describes state supremacy over church institutions without necessarily making the ruler a religious authority.
Byzantine Empire: The medieval Eastern Roman Empire, centered on Constantinople and governed by Christian emperors. Its emperors frequently intervened in church affairs, making it a central case in discussions of caesaropapism.
Papal supremacy: The doctrine that the pope holds supreme authority over the Catholic Church. It places ultimate church authority in the papacy rather than in a secular ruler.
Council of Nicaea: The Christian council convened at Nicaea in 325 to address disputes including Arianism. Emperor Constantine’s involvement made the council an early example of imperial participation in doctrinal settlement.
Church–state relations: The patterns of authority, cooperation, and conflict between religious institutions and political governments. Caesaropapism is one arrangement within the wider range of church–state relations.
Constantine the Great: Roman emperor from 306 to 337 who supported Christianity and convened the Council of Nicaea. His imperial role in the Council of Nicaea illustrates early Christian rulers shaping church affairs.
Theocracy: A system of government in which religious authority directly governs political affairs. It reverses the usual direction of caesaropapist influence, with religious authorities governing the state.
Iconoclasm: The rejection or destruction of religious images, especially during Byzantine controversies over icons. Imperial policies toward icons show how rulers could shape worship and provoke church conflict.
Imperial church: A church closely integrated with an empire’s political institutions and supported by imperial power. Such integration can give an emperor leverage over church leadership and administration.
Justinian I: Byzantine emperor from 527 to 565 who reorganized law, administration, and imperial religious policy. His legislation and religious interventions exemplify strong imperial influence over church institutions.

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