Karl Barth’s theological project remains the subject of much discussion, especially surrounding his account of the person of Jesus Christ and its relation to that of the knowledge of God. The extent of Barth’s Chalcedonianism, the nature of his ‘actualism’, and his attitude towards metaphysics are all live debates. Educated in liberal Protestantism, Barth assumed the old ‘two schools’ theory of patristic theology and of Chalcedon, leading him to formulate a ‘twofold’ Christology that attempted constantly to switch between the two idioms. The implications of this inherent tension can be discerned in his work as ripples from the Christological centre. His theology has therefore been categorised variously as Alexandrian and Antiochene, Apollinarian and Nestorian, orthodox and modern. Recent criticism of the two schools theory has led many patristics scholars to a reassessment of the Nestorian Controversy, the work and impact of Cyril of Alexandria, and the theological vision of Chalcedon. These insights may shed light on the debates in Barth scholarship. How can Barth’s retrieval of Chalcedonianism for his theological project be assessed? How might our assessment of this be attenuated by the retrieval of Cyril of Alexandria and of Chalcedon that has taken place since Barth’s death? Can Barth’s theological project be taken further today than he himself was able with these resources? This thesis considers the dynamics of the Nestorian controversy, the intent of Chalcedon and the scheme of divine-human relations it envisions, the Chalcedonian resonances of Barth’s actualism, the Christology of the Church Dogmatics, and the various assessments that have been made of it. Chalcedonian Christology in the Cyrillian idiom may usefully contribute to the ongoing debates in Barth scholarship and may prove a powerful resource for the extension of Barth’s Christologically-controlled theological project. More, it may contribute towards understanding the relationship between Christology and the doctrine of revelation in broader systematic terms, since Christology can and will shape theology in every way.