Council of Seleucia-Ctesiphon
The Council of Seleucia-Ctesiphon, also called the Council of Mar Isaac, met in AD 410 in Seleucia-Ctesiphon, the capital of the Persian Sassanid Empire. Convoked by King Yazdegerd I, it organized the Christians of his empire into a single structured Church, which became known as the Church of the East. It is often compared to Constantine's Edict of Milan, approximately a century earlier. The events of this council are documented in the Synodicon Orientale.
Previously, the Persian state persecuted those Christians, fearing that their loyalty lay with the Roman Empire, which under Constantine the Great had legalized Christianity and with which the Sassanid Empire was repeatedly at war. Persecution had been most severe under Shapur II. Shapur I, the second Shahan-shah of the Sasanian dynasty had advanced as far as Antioch in 260, and both he and Shapur II deported eastward much of the population of the invaded territories to strengthen the Persian economy.
Yazdegerd I adopted a policy of engagement with the Roman Emperor in Constantinople and with the Christian minority in his own empire. In 409, he allowed the Christians to worship openly and to have churches. Zoroastrianism continued to be the official religion, and apostasy from it was punishable by death.
At the suggestion of a bishop from the Roman side of the frontier, a council of bishops was called to organize the Persian Christians as a single Church, with a single bishop in each diocese and with one bishop to act as their head collectively throughout his empire.
Establishment of the Church of the East
The Council, presided over by Mar Isaac, archbishop of Seleucia-Ctesiphon, arranged the Persian Church in ecclesiastical provinces, with the bishops in each province grouped around a metropolitan, the arrangement approved by the First Council of Nicaea in the civil provinces of the Roman Empire.The archbishop of Seleucia-Ctesiphon, the capital city, who is referred to in the acts of the council as the Grand Metropolitan, was to hold authority throughout the Church and for that reason was called the Catholicos.
The 410 council set up six provinces, which became known as the interior provinces, according as other provinces, referred to as exterior provinces, were recognized further afield within the empire and even beyond it.
In order of precedence, the six interior provinces were:
- Seleucia-Ctesiphon, in what is now central Iraq
- Beth Lapat, in western Iran
- Nisibis, on the border between today's Turkey and Iraq
- Prat de Maishan, Basra, southern Iraq
- Arbela, Erbil, Kurdistan region of Iraq
- Karka de Beth Slokh, Kirkuk, northeastern Iraq