The “Formula of Reunion”
After the First Council at Ephesus that condemned both John of Antioch and Nestorian’s view as heresy in 431 A.D., Cyril of Alexandria approached John to work out in their theological differences and reconcile with each other by compromising on certain doctrinal differences. This reconciliation is known as the “Formula of Reunion” that took place in 433 A.D.
In this formula, Antiochenes acknowledged Cyril’s view of referring the Virgin Mary as the theotokos or “Mother of God” was appropriate. Same way, Cyril also acknowledged the Antiochenian understanding of Chris’s bearing “two natures” – human nature that is distinguishable from his divine nature – that Jesus is “Logos made flesh (John 1:1, 14).”
The ultimate solution of the “Formula of Reunion” is: Jesus Christ as one person but two distinctive nature – human and divine.
The First Council at Ephesus in 431 A.D. formally condemned Nestorius‘ view as heresy. Cyril of Alexandria was very concerned for the questioned raised by Nestorius and accused Nestorius publicly in the council. Cyril appealed to Celestine of Rome, Church Father who held papal authority from 422 to 432 to excommunicate Nestorius for his lowly view of Christ’s divine and human nature. The Emperor Theodosius II (401–450) called for the Third Ecumenical Council to decide on veneration of Virgin Mary who was titled as the “Mother of God“. Delegates from the Eastern and Western churches came to the council. For some reason, delegates from the East were late to arrive in the council. So, Cyril conducted the council in the absence of Nestorius and condemned him and his teaching in his absence.
John I of Antioch learned upon his arrival to the council that Nestorius had been already condemned. Now, Nestorius in support of John I of Antioch held their own synod that condemned and deposed Cyril and the previous council in Ephesus. Later, both sides were deposed and exiled by the emperor. Afterwards, West came along and condemned Nestorius the heretic.