He thereupon threw his weight behind Nestorius, gathered the bishops who had come with him, and excommunicated both the Patriarch of Alexandria and the Bishop of Ephesus.
When the followers of the Patriarch of Alexandria saw the baseness of his action, a grave dispute broke out. They left Ephesus, and the partisans of the Alexandrian patriarch and the Eastern bishops became two rival factions, until King Theodosius persisted and finally reconciled them.
The Easterners then drew up a document in which they affirmed the sound Creed. They stated: “Mary, the holy Virgin, gave birth to God—our Lord Jesus Christ—who is of the same divine nature as His Father and of the same human nature as mankind.” They confessed two natures, yet one person and one hypostasis, and they anathematized Nestorius. The document was sent to the Patriarch of Alexandria, who accepted it and replied, declaring his agreement.
Some people claimed that when he accepted the Easterners’ document he changed his position and no longer acknowledged two natures in one person. Saʿīd ibn al-Batrīq says, “They are lying, for his writings clearly affirm this.”
He then forwarded a copy of the Easterners’ document to a group of bishops, informing them that the Easterners had returned to the faith and were no longer in accord with Nestorius.
He further said: “From the second council—the one hundred and fifty bishops who met in Constantinople and anathematized Macedonius—to this council of two hundred bishops who met in Ephesus against Nestorius, fifty-one years elapsed.”