Which council dealt with the issue of the nature of Christ?

The Council of Chalcedon, which took place in 451 AD, specifically addressed the nature of Christ, affirming the doctrine of the dual nature of Christ as both fully divine and fully human. This council was pivotal in clarifying the relationships within the Trinity and establishing the orthodox understanding of Christ's personhood, particularly in response to various heresies of that time, such as Nestorianism and Monophysitism.

The Chalcedonian Definition that emerged from the council declared that Christ has two natures, one divine and one human, which exist concurrently without confusion or separation. This doctrinal formulation helped to unify the Church's teaching about Christ amidst growing divisions and disputes regarding His identity.

In contrast, the other councils mentioned did not primarily focus on the nature of Christ. The First Council of Nicaea concentrated on the relationship between the Father and the Son, particularly combating Arianism, which denied the full divinity of Christ. The Council of Constantinople addressed issues related to the Holy Spirit and affirmed the Nicene Creed. The Council of Trent, much later, was concerned with reforming church practices and was not focused on Christological debates. Thus, the Council of Chalcedon's clear and comprehensive definition regarding the nature of