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Cyriacus I of Byzantium
Bishop of Byzantium
Term ended230
Personal details
DenominationEarly Christianity

Cyriacus I (? – 230) succeeded Philadelphus as Bishop of Byzantium and governed the local church for 13 years. In some catalogues appears under the name Cyrillianus.


Titles of the Great Christian Church Preceded byPhiladelphus Bishop of Byzantium 217–230 Succeeded byCastinus