But to Calvin and others, this idea of the communication of divine attributes to the human nature was seen as a violation of the Council of Chalcedon (a.d. 451), which affirmed that the two natures of Christ, human and divine, are united in such a way as to be without mixture, confusion, separation, or division, each nature retaining its own attributes.So for Calvin and most of the Reformers, transubstantiation manifested a form of this heresy.