Eutychianism

Eutychianism, also known as Real Monophysitism,[1][2][3] refers to a set of Christian theological doctrines derived from the ideas of Eutyches of Constantinople (c. 380 – c. 456).

In 325, the issue of how to reconcile the claims of monotheism with the assertion of the divinity of Jesus of Nazareth was largely settled at the First Ecumenical Council held at Nicaea.

"[8] However, neither the Nicene Creed nor the canons of the Council provided a detailed explanation of how God became human in the person of Jesus, leaving the door open for speculation.

It seemingly rejected any attempted answer that stressed the duality of Christ's natures to the expense of his unity as a single hypostasis (understood to mean "person").

[12] Miaphysites rejected that definition as verging on Nestorianism and instead adhered to the wording of Cyril of Alexandria, the chief opponent of Nestorianism, who had spoken of the "one (mia) nature of the Word of God incarnate" (μία φύσις τοῦ θεοῦ λόγου σεσαρκωμένη mia physis tou theou logou sesarkōmenē).