The Council of Chalcedon met in 451 C.E. and over 500 bishops were in attendance. The focus of the council was to develop a definitive understanding and definition of the incarnation. The majority of bishops did not want to announce a new creed but rather uphold the Nicene Creed. However, Emperor Marcian thought that there was a need for a new creed due to recent contrasting views about Jesus. Responding to the views of Eutyches was the primary focus of the council. Eutyches advocated a newly revamped Apollinarianism (or monophysitism). Eutyches argued that Christ had one nature after the union, meaning that the human nature had merged with the divine nature “as a drop of honey mingled with the ocean.” The Council of Chalcedon condemned the views of Eutyches and confirmed and strengthened the statements about Christ as read in the Nicene Creed. The council declared Christ’s two natures— that he is perfectly God and perfectly man at the same time. Christ is the God-Man “without confusion, without change, without division, without separation; the distinction of natures being in no way annulled by the union, but rather the characteristics of each nature being preserved and coming together to form one person and substance.” From the Council of Chalcedon, the Chalcedon Creed was formed and this creed continues to be the Christological standard for most Christian traditions.
 T.G. Weinandy, “Chalcedon, Council of” in New Dictionary of Theology: Historical and Systematic (NDT) eds. Martin Davie et al. (Downers Grove, Ill: IVP Academic, 2016), EPUB edition.  H.D. McDonald, “Monophysitism” in NDT, EPUB edition.  McDonald, “Monophysitism,” in NDT, EPUB edition.  D.Demarest, “Creeds,” in NDT, EPUB edition. “The Chalcedon Formula” http://anglicansonline.org/basics/chalcedon.html