The minutes of the Council of Seleucia-Ctesiphon (also known as Synod of Mar Isaac), however, tell a different story.

In 410, at the Council of Seleucia-Ctesiphon, Mar Isaac was elected as Catholicos of the Church of the East.

The Church of the East went through major consolidation and expansion in 410 during the Council of Seleucia-Ctesiphon, held at the Sassanid capital (in Asuristan).

According to the Chronicle of Seert, Bishop David of Perat d'Maishan was present at the Council of Seleucia-Ctesiphon, around 325, and sailed as far as India.

At the Council of Seleucia-Ctesiphon, with the approval of the Sassanid king, a formal Patriarchate was established (see List of Patriarchs of the Church of the East).

The Council of Seleucia-Ctesiphon, also called the Council of Mar Isaac, met in AD 410 in Seleucia-Ctesiphon, the capital of the Sassanid Empire of Persia.

Acts of the Council of Seleucia-Ctesiphon (26 spurious canons of a synod held in 410) He also wrote hymns on the Holy Eucharist, on the Cross, and on saints died in Shapur's persecution.

In the 5th century this was claim strengthened and Isaac (or Ishaq, 399-c.410), who organized the Council of Seleucia-Ctesiphon, used the title of bishop of Selucia-Ctesiphon, Catholicos and Head over the bishops of all the Orient.

At the subsequent Council of Seleucia-Ctesiphon of 410, the Christian communities of Mesopotamia renounced all subjection to Antioch and the "Western" bishops and the Bishop of Seleucia-Ctesiphon assumed the rank of Catholicos.

Recent discoveries have shown that the earliest known introduction of "and the Son" into the Nicene Creed may have been the work of a local council in the east, the Council of Seleucia-Ctesiphon in Persia in about 410.