Chalcedonian Creed
Date: AD 451
In response to Nestorian teachings, the Chalcedonian formulation defines that Christ is "acknowledged in two natures", which "come together into one person and one hypostasis".
The Council of Ephesus in AD 431 forbade the making of any new creed. The Council of Chalcedon, which met in 451 to confront new errors, chose to issue a decree to affirm earlier versions of the Nicene Creed (both the 325 and the 381 versions) and also to offer a concise clarification regarding the church’s teaching about the person of Christ. The council then promptly banned anyone else from making a new creed. While not a complete creed of the Christian faith, this clarifying statement, or definition was adopted by the eastern and western church as a response to several heresies regarding the nature of Christ.
This clarification was the clearest statement to date on the person of the Lord Jesus Christ. It confesses who Christ is now: God and man, one person in two natures (hence its language of both natures coming together in one person). Unlike earlier creeds, it does not emphasize the actual event of the incarnation, the person of the Son taking to himself humanity. Famously, it also offers a series of denials about Christ when it teaches that the natures of Christ “undergo no confusion, no change, no division, no separation.” This “negative” theology reflects a belief among many Christians that much of what we say about God. and perhaps the best of what we say about God, consists in saying what he is not.