IssuesBishops met in present-day Turkey in the summer of 431 to address Nestorianism. Nestorius was the Patriarch of Constantinople who was teaching that Mary is the Christotokos but not Theotokos. Ironically (or maybe not), the council met at the Church of Mary in Ephesus. Nestorius believed his views orthodox and supported the convening of the council. Another issue was Pelagianism, the belief that original sin did not stain humanity. Pelagianism states that humans are capable of living a sinless life without divine intervention.
ResultsThe council ruled that Mary is indeed Theotokos, bearer of God. Christ is fully human and fully divine. Pelagianism was also condemned. Also, the Nicene Creed was confirmed (again) as the statement of faith for the Church.
There were many followers of Nestorianism that schismed as a result of the council. One was the Persian Church, which under persecution by Zoroastrians, aligned with the more local group so as to appear less influenced by foreign powers. In 1994, the Common Christological Declaration affirmed the shared views between the Catholic Church and the Assyrian Church of East.
HeresiesNestorianism sounds like the focus is on Mary, but as always, Mary points to Jesus. To deny that Mary is Theotokos is to deny Christ’s divinity. Nestorius’ argument separated the incarnate Christ from the divine Logos, making him fully human at one point and fully divine at another. I think this is an easy mistake to make, and unless specifically addressing dualism, I don’t see how the belief affects other parts of theology. There are still churches that follow the Nestorian teaching, as indicated by the Common Christological Declaration that just took place 20 years ago.
There is still Pelagianism present in many churches, although today, many go further to deny original sin in any form. Variants of it can be found in churches that reject infant baptism. But Pelagian ideas also state simply living a moral life is what gets you into heaven, not Christ’s resurrection. This idea of Pelagianism is still found when people equate being a good person with earning salvation.