Final answer:
The Council of Chalcedon in 451AD addressed the heresy of Monophysitism, affirming the orthodox belief in the Dyophysite nature of Christ, resulting in a significant schism within the Christian Church.
Step-by-step explanation:
The Council of Chalcedon that convened in 451AD was a significant event in the history of Christianity. It aimed to resolve controversies regarding the nature of Christ and address heterodox beliefs that were causing division within the Church. The heresy that the Council of Chalcedon specifically addressed was Monophysitism, which posited that Jesus's divine and human natures were merged into a single nature, contradicting the orthodox Dyophysite view that Jesus was both fully divine and fully human.
The Council concluded that the Monophysite position was heretical, leading to a rift that resulted in the separation of churches such as the Coptic Church that held to the Monophysite doctrine. Monophysitism was prevalent in regions including Egypt, and the Council's decision to denounce it caused a schism that had a lasting impact on the Christian world.
The Council of Chalcedon's decision affirmed the doctrine of Dyophysitism, which stated that Christ has two distinct natures, one divine and one human, existing in unity but without confusion or mixture. This became a cornerstone of orthodox Christian theology and contributed to the shaping of Christian doctrine as we know it today.