Legates of Leo IX lay a bull of excommunication on the altar of Hagia Sophia and Patriarch Cerularius answers in kind; the mutual anathemas formalize the rupture between Rome and Constantinople.
Tagged: Schism Catholic Christian Eastern Orthodox
The Event
- Date
- 1054 (exact)
- Also called
- East-West Schism, Schism of 1054
- Era
- Medieval; Standard ecumenical periodization
- Location
- Constantinople; today Istanbul, Turkey
- Traditions
- Christianity
- Streams
- Catholic, Eastern Orthodox
- Key figures
- Michael Cerularius, Cardinal Humbert
How the Tradition Tells It
The events of 1054 were mutual excommunications of legates and a patriarch, not a single act of separation by whole churches; local relations between Greek and Latin Christians varied widely for centuries afterward.
Connections
- Second Council of Nicaea; followed_centuries_of_drift
Primary Sources
- The bull of excommunication (1054)
- Michael Cerularius, synodal reply
Secondary Sources
- Pelikan, The Christian Tradition, vols. 1–5 (Chicago, 1971–1989)
- MacCulloch, A History of Christianity (Allen Lane, 2009)
Provenance: HIST-0022; confidence 0.95; accessed 2026-10-26.
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