council · 410 · Seleucia-Ctesiphon
Under the protection of Yazdegerd I, forty bishops met at Seleucia-Ctesiphon in 410 with Marutha of Maiperqat carrying the western church's greetings. They received the faith and canons of Nicaea and set the catholicos over every see of the empire: the Church of the East steps into history as an ordered body.
The Council of Seleucia-Ctesiphon, also called the Council of Mar Isaac, met in AD 410 in Seleucia-Ctesiphon, the capital of the Persian Sasanian Empire. Convened by King Yazdegerd I (399–421), it organized the Christians of his empire into a single structured church, which became known as the Church of the East. The Council is often compared to Constantine's Edict of Milan from approximately a century earlier. The events of this council are documented in the Synodicon Orientale.
Organizing the church of the Persian empire after the peace of Yazdegerd I.
The synod of Isaac: Nicaea received, the catholicos of Seleucia-Ctesiphon set over all the bishops of Persia — the Church of the East constituted.