Miaphysitism (sometimes called henophysitism) is a Christological formula of the Oriental Orthodox Churches and of the various churches adhering to the first three Ecumenical Councils. Miaphysitism holds that in the one person of Jesus Christ, Divinity and Humanity are united in one or single nature ("physis"), the two being united without separation, without confusion, and without alteration.
Historically, Chalcedonian Christians have considered Miaphysitism in general to be amenable to an orthodox interpretation, but they have nevertheless perceived the Miaphysitism of the non-Chalcedonians to be a form of Monophysitism. The Oriental Orthodox Churches themselves reject this characterization.
The term "miaphysitism" arose as a response to Nestorianism. As Nestorianism had its roots in the Antiochene tradition and was opposed by the Alexandrian tradition, Christians in Syria and Egypt who wanted to distance themselves from the extremes of Nestorianism and wished to uphold the integrity of their theological position adopted this term to express their position.
The theology of miaphysitism is based on an understanding of the nature (Greek φύσις physis) of Christ: divine and human. After steering between the doctrines of docetism (that Christ only appeared to be human) and adoptionism (that Christ was a man chosen by God), the Church began to explore the mystery of Christ's nature further. Two positions in particular caused controversy:
In response to Eutychianism, the latter Council adopted dyophysitism, which clearly distinguished between person and nature, stating that Christ is one person in two natures, but emphasizes that the natures are "without confusion, without change, without division, without separation".