Council of Chalcedon

Building upon Ephesus, the Council of Chalcedon provided the definitive Christological statement of the early Church. It addressed the Monophysite heresy, which claimed that Christ had only one nature, a blend of human and divine. The Council produced the Chalcedonian Definition, clarifying that Jesus Christ is one Person subsisting in two distinct, unconfused, and undivided natures: fully God and fully man. This theological masterpiece, heavily influenced by Pope Leo the Great's 'Tome', remains the bedrock of orthodox Christology.