The First 6 Ecumenical Councils:
This is what you believe

[Note: As with any meeting of many leaders at the same place, the councils discussed the main idea, which in this case was the heresy, plus other concerns. This article will only cover the heresies.]

Council 1: The Council of Nicaea, 325

• Heresy: Arianism founded by Arius. Arius believed that the Father created Son, therefore, there was a time when the Son did not exist.
• Decision: The council declared that Jesus has always existed.

Council 2: The First Council of Constantinople, 381

• Extra: At this council, Theodosius decided to end Arianism as a threat to Christianity. The council adapted the Nicene Creed by further defining who Christ was (thereby enlarging the section of the Creed that describes Christ). This adapted Creed is known as the Niceno-Constantinopolitan Creed, although it is frequently referred to as the Nicene Creed.
• Heresy: Apollinarius raised the question of how Christ was constructed. He believed that humans have a body, soul, and spirit, and that Jesus had a human body and a soul but not a human mind. Instead, he believed that the logos (John 1:1) controlled Jesus instead of a human mind. The other bishops at the Council of Constantinople believed this demoted Jesus to be less than fully human; therefore, he would not be a sufficient sacrifice for humanity's sins.
• Decision: The council declared that Jesus was fully God and fully human.

Council 3: Council of Ephesus, 431

• Heresy: Nestorius (pronounced like it looks: "nes-to-ri-us") was the bishop of Constantinople, and he disagreed with a term that was becoming popular, that Mary (the mother of Jesus) was the "Mother of God." He believed that Mary was the mother of Christ, meaning the human aspect of Jesus Christ. He taught that Christ was two separate beings or people, divine and human. This concept allowed for the divinity of Christ to overwhelm the humanity of Christ. The reason for this distinction was that Nestorius believed that Jesus Christ was two persons, with the human person being born and then suffering and dying on the cross but not the divine person. The problem (really, heresy) is that this rejects the atonement, where Jesus Christ, as both God and man, took upon himself all sin and paid the punishment for humans.
• Decision: The council declared that Christ was one person with two natures.
• Extra: The council also declared that Mary, the mother of Jesus, remained a virgin her entire life and gave her the title of "Mother of God." [Which Protestants do not accept.]

Council 4: Council of Chalcedon, 451

• Heresy: Eutyches (pronounced "you-ti-cuss") spoke out against Nestorius at the Council of Ephesus. Yet his own theology went too far in the other direction. Whereas Nestorius believed that the divine and human natures within Jesus Christ were further apart than other bishops accepted, Eutyches believed they were more closely intertwined than other bishops accepted. This view is known as "monophysitism," or "one nature."
• Decision: The council declared that the two natures of Christ form one person and one hypostasis (meaning one substance). The result is that the divine and human natures are equally "mixed" or "intertwined" in Christ, without one overwhelming the other.

Council 5: Second Council of Constantinople, 553

• Heresy: This council mainly supported the decisions of the previous council. After the Council of Chalcedon ended, some lingering belief of monophysitism continued, especially in the east. This council was an attempt to provide some common ground between eastern and western Christianity, but it did not succeed. [This was one reason the church split in 1054 into Catholics and Orthodox.]

Council 6: Third Council of Constantinople, 680-681

• Heresy: This council defeated two ideas that developed out of the one person-two natures doctrine declared at the Council of Chalcedon. Monoenergism is the idea that Christ had two natures but one energy. Monothelitism is the idea that there is one will (and not two wills that could come naturally out of a two-natures doctrine).