Third Council of Constantinople (680-1)

Heraclius (610-41) took over an empire which had been losing ground against its enemies in the north (the Avars and Slavs) and in the east (the Sassanians who would soon be supplanted by the Saracens).

He worried that the Monophysite Christians who were isolated from the Western Church might join the eastern enemies of the Byzantine empire and to find a solution to the disputes between the antagonistic groups he summoned the Sixth Ecumenical Councils.

The previous compromise formulas defining the nature of Christ were condemned and the doctrines of the Council of Chalcedon (451) were accepted as truth. To bring peace to the Church, a new formula which skirted the question of natures by claiming that while Christ had 'two natures,' as confirmed at Chalcedon he had only a 'single will', was proposed by the efforts of the emperor Heraclius shortly before his death.

Although this proposal was accepted by the East, Rome opposed it and consequently it did not achieve the unity that Heraclius had expected.

However, the claim was found inconsistent with the reality of Jesus' human nature and to settle the 'Monothelete' doctrine, also called Monotheleotism Constantine IV (668-85) summoned the Third Council of Constantinople. The meetings were held in the Trullos, or the 'Domed Hall' of the Great Palace and at the end the doctrine of the 'single will' was condemned and the Chalcedonian faith affirmed.