Central to Christianity is the belief that Jesus is both the Son of God and lived on earth as a human being. The orthodox interpretation of this belief is that Jesus is both fully divine and fully human, having two natures, a divine nature and a human nature, distinct from, but very closely related to, each other.
Monophysitism - the word is pronounced with the stress on the second syllable, mo-NO-fi-sai-tizm IPA: /mɒˈnɒfɪˌsaɪtɪzm/ - holds, contrary to the orthodox view, that Jesus has only one nature, and that his humanity is in some way included within, or absorbed by, his divine nature. Monophysitism thus errs, in the eyes of the orthodox, by over-emphasising Jesus' divinity at the expense of his humanity. The doctrine was widely accepted, particularly in the eastern half of the Roman Empire, during the final decades of the fourth and the first half of the fifth centuries, but was condemned as heretical by the fourth ecumenical Council of bishops meeting at Chalcedon in 451. However, the present-day Coptic and Jacobite Churches still hold the Monophysite doctrine.
Different versions of Monophysitism may be distinguished according to the different ways in which Jesus' human attributes were said to be accommodated within his divine nature. For example, Apollinaris the Younger (died 390), bishop of Laodicea in Syria, maintained that Jesus' single divine nature was made up of different 'parts', some of which were human, but insisted that his νους (nous, the word used by some Greek philosophers to refer to the highest and most authoritative 'part' of the mind) was entirely divine. In contrast Eutyches (c380-c456), a priest and archimandrite (i.e., head of a monastery) in Constantinople, argued that the divine and human 'elements' in Jesus' single nature were so thoroughly intermingled that their relationship was best characterised by the metaphors of fusion or absorption: Jesus' humanity, he said, was incorporated into his divine nature as 'a drop of honey would be dissolved in the sea'.