Last week we looked at what defines a heresy and how the church has used heresies as opportunities to clarify and solidify doctrines so that we can be confident in the truth. We also examined the heresy of Gnosticism, which held many false beliefs, and how St. Irenaeus was able correct them through his writings. Today, we’ll examine the heresies of Arianism and Nestorianism.


Arius was a problem from the beginning (256-336 AD). After settling in Alexandria, he was ordained a deacon, but soon was excommunicated for following another, earlier heresy. After the bishop who excommunicated him was martyred, that bishop’s successor reinstated Arius in the Church and ordained him a priest. He managed to enjoy a good reputation for a little while, until a new successive bishop heard about what he had been preaching and called Arius to explain himself. I will use Arias’ own words to reveal his error:

If the Son is a real Son, then a Father must exist before a Son; therefore the Divine Father must have existed before the Divine Son. Therefore, He is a creature; the greatest indeed and the eldest of all creatures and Himself a God, but still created; therefore, like all creatures, of an essence or substance which previously had not existed.

Arius claimed that Jesus was a created being and thus had a beginning in time and was not eternally God, like the Father. After being corrected by the bishop, Arius suffered from pride and stubbornly persisted in his faulty belief, which, remember, is one of the components of heresy. Thus, Arianism was born. In short, the Arian heresy is an attack on the Trinitarian nature of God as three persons in one nature, existing eternally, which is the central truth on which our Faith is founded.

In response to the quickly spreading heresy, the Church called the Council of Nicaea in May of 325. The participants of the council understood that God, as a created God, is a contradiction of terms because, by nature of being God, the eternal being, He cannot be created and have a beginning. However, it was not enough for them to know it, they had to make the doctrine clear, without room for faulty interpretation, and ensure it was taught correctly to the people. At this time, the Apostle’s Creed existed and was recited as a statement of faith by believers, but it did not clarify that the three members of the Trinity were of one divine nature. It was proposed that the word homo-ousios, meaning “of the same essence or substance,” be added to the creed to indicate that the Father and Son share a nature. There was some objection to that addition because the word homo-ousios is not found in Scripture. That objection was overruled because it demonstrated precisely how scripture can be misinterpreted when one is left to one’s own devices, like Arius had done. We need the Church to interpret Scripture and define doctrine for us for situations like this one. So, after working through it, the Council of Nicaea produced the Nicene Creed in which we proclaim the words, “I believe in one Lord Jesus Christ, the Only Begotten Son of God, born of the Father before all ages. God from God, Light from Light, true God from true God, begotten, not made, consubstantial (homo-ousios) with the Father; through him all things were made.” Now, when you recite the Nicene Creed in Mass, you can understand it’s origins and why the words used are necessary for a clear understanding of the Trinity and of Jesus’ eternal, divine nature.


Nestorius (386-451 AD) lived in Antioch and was eventually chosen to be a patriarch in Constantinople in 428. His heresy purports that Christ was actually two separate persons, and that the human Christ’s body is a temple that the divine Christ lives inside. Going further, Nestorius claimed that because He is two persons, Mary only gave birth to the human Christ and not the divine Christ. This would preclude her from being called the Mother of God. Nestorianism adopted the word Christotokos — “Mother of Christ,” in objection to the Catholic term of Theotokos — “Mother of God.” St. Cyril (c 376-444 AD), who was the patriarch of Alexandria, heard what Nestorius was preaching and immediately condemned the false teaching. The two then went back of forth through quite an exchange of a series of letters. St. Cyril’s writings were compiled in the book, On the Unity of Christ, in which he defends the truth that Jesus is one man with two natures that are inseparable. Needless to say, the two patriarchs were not able to resolve their differences and their conflict was eventually brought to Pope Celestine I. The pope concurred with St. Cyril and demanded that Nestorius retract his statements within 10 days, which he did not do, thereby solidifying his heresy and opposition to Church.

Operating as the Church does in dealing with controversy regarding doctrine, the Council of Ephesus was called in 431 AD. The council was not without some drama because men on both sides of the issue were participating, but as always, the Holy Spirit was there to guide and protect the outcome. From this council, the dogma of Mary as Theotokos was officially declared stating:

If anyone does not confess that God is truly Emmanuel, and that on this account the holy virgin is the “Theotokos” (for according to the flesh she gave birth to the word of God become flesh by birth) let him be anathema. (The Council of Ephesus, 431 AD)

As with other teachings of the Church that are based on already established beliefs, this doctrine was not some newly developed understanding of Mary’s role as the Mother of God. We know this by virtue of St. Cyril’s and Pope Celestine’s objections to Nestorius’ teachings. However, councils give the Church the opportunity to write and codify official definitions and doctrines so as to avoid future misinterpretation. Also note, that with regard to Marian dogmas and doctrines, they are not about Mary herself, but serve to protect the truth of who her Son is. So, in this case, the dogma of Theotokos protects the truth that Jesus Christ is one God with two unified natures, and for Mary to give birth to one, she necessarily had to give birth to both. Then, a short 20 years later, in 451, the Council of Chalcedon was called, which declared “that in Christ the two natures, each retaining its own properties, are united in one subsistence and one person,” thus defining the doctrine of the Hypostatic Union and affirming Mary as Theotokos.

This week, consider the growing pains the Church had to endure for you to have the truth at your fingertips today and how blessed we are to have had the gift of so many great saints and holy men and women to work these things out for us. Consider how, just like He does for the Church, God continually sheds light into your life, revealing things you had not noticed before. He teaches you and reveals Himself to you slowly, according to your readiness in understanding what He has to offer you. Ask the Holy Spirit to always protect you from false teaching as you seek to understand God more fully.

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Heresies – Using Error to Clarify Divine Truth (Part 1)