How did the Council of Chalcedon define the nature of Christ?

The Council of Chalcedon, held in 451, established the definitive orthodox doctrine regarding the nature of Christ, aiming to resolve long-standing tensions between the Alexandrian and Antiochene theological schools.12

The council’s definition, heavily influenced by the Tome of Pope Leo I, declared that Jesus Christ is one and the same Son, perfect in both deity and humanity. The council affirmed that Christ exists in two natures—divine and human—which remain "without being mixed, transmuted, divided, or separated".13

Crucially, the council maintained that the distinction between these two natures is not abolished by their union; rather, the identity of each nature is preserved, and both concur into one single person and being (hypostasis). By this formula, the church rejected both the Nestorian tendency to split Christ into two persons and the monophysite view that Christ possessed only a single, divine nature. This settlement remains the foundational statement on the person of Christ for most of the Christian church.145