This heresy begins a three week series on related heresy. First up: one of the larger "ancient" heresies.
Monophysitism teaches that after the union of divine and human in the incarnation that there was only one nature in Christ—either divine (generally emphasized) or a synthesis of divine and human (as taught in Miaphysitism). This came into being after some rejected the 451 Council of Chalcedon, where Christ’s two natures were formally codified by the church. Members of the Oriental Orthodoxy Church, who believe in Miaphysitism, split from the main church over this distinction after the Council’s affirmation of two natures. Apollinarianism and Eutychianism are two major Monophystite heresies (although Apollinarianism predates Monophysitism), and Monophysitism is considered an overreaction in response to Nestorianism and their teaching that Christ was two separate people (the man and the divine), but really it is almost a better juxtaposition with Arianism’s denial of Christ’s divinity. It was condemned at the 680 Third Council of Constantinople, along with the two “compromised” composed as a “middle ground” to Monophysitism: Monoenergism and Monothelitism.