Diptych

See Diptychs — the hinged tablets listing those commemorated at the Liturgy; inclusion signals full communion.

Diptych is the singular of diptychs — already defined. The singular form emphasizes the individual character of liturgical commemoration: a person's name on the diptych means their soul is prayed for at every Liturgy. Removal of a bishop's name from the diptychs of another church is the practical act of breaking communion. The Byzantine emperors were extremely sensitive to diptych politics: inclusion or exclusion from Constantinople's diptychs had direct diplomatic implications.