Caesaropapism

Caesaropapism describes a configuration of church–state relations in which the head of state also exercises supreme authority over ecclesiastical matters — appointing senior clergy, convening councils, and shaping doctrine or liturgy. The term is a 19th-century coinage (from Caesar and papa) used by historians and political theorists to characterize, above all, the Byzantine Empire, where emperors from Constantine I onward summoned ecumenical councils, intervened in theological disputes such as Iconoclasm, and treated the Patriarch of Constantinople as a subordinate figure within the imperial order.

The concept is contested. Many Byzantinists, notably Gilbert Dagron in Emperor and Priest (1996), argue that "caesaropapism" overstates imperial control and obscures the more complex symphonia doctrine — a theory of harmonious cooperation between imperium and sacerdotium set out in Justinian's Novella 6 (535 CE). Under symphonia, emperor and patriarch held distinct but complementary spheres; abuses occurred, but the church retained doctrinal autonomy in principle.

Beyond Byzantium, the label has been applied — with varying accuracy — to:

• Russia after 1721, when Peter the Great abolished the Moscow Patriarchate and replaced it with the Holy Synod, a state department supervised by a lay Ober-Procurator.
• Tudor England following the Act of Supremacy (1534), which made Henry VIII "Supreme Head" of the Church of England.
• Certain Protestant Landeskirchen in the Holy Roman Empire after the Peace of Augsburg (1555), under the cuius regio, eius religio principle.

In contemporary international relations, the term resurfaces in analyses of states where political leaders cultivate tight institutional links with a national church — for instance, debates about the Moscow Patriarchate's alignment with the Kremlin, or the role of religion in some Gulf monarchies. It is generally contrasted with theocracy (clerical rule over the state) and with secularism or laïcité.