Saint Constantine

Saint Constantine may refer to:

Constantine I, Roman Emperor and a convert to Christianity
Constantine of Dumnonia, King of Cornwall
Constantine of Strathclyde, probably fictitious King of Strathclyde
Constantine (British saint), various figures of this name
Constantine the Jew, Byzantine monk
Constantine XI, last Byzantine emperor, unofficial Catholic Saint
St Cyril, born Constantine, Christian theologian from Thessalonica and Christian missionary among the Slavs with his brother Methodius