[2] The council settled a set of theological controversies that went back to the sixth century but had intensified under the emperors Heraclius (r. 610–641) and Constans II (r. 641–668).

Heraclius had set out to recover much of the part of his empire lost to the Persians and had attempted to bridge the controversy with monophysitism, which was particularly strong in Syria and Egypt, by proposing a moderate theological position that had as good support in the tradition as any other.

When Heraclius' grandson Constans II took the throne, he saw the controversy as threatening the stability of the Empire and attempted to silence discussion by outlawing speaking either in favor or against the doctrine.

[4] At Constantinople in around 653, some accused the Pope of supporting revolution; this was regarded as high treason, and Martin was accordingly arrested, tried, condemned and sent into exile, where he soon died.

[5][page needed][6] After Constans' son and successor, Constantine IV had overcome the Muslim siege of Constantinople in 678, he immediately set his sights on restoring communion with Rome: he wrote to Pope Donus suggesting a conference on the matter.

Still, his successor, Pope Agatho, agreed to the Emperor's suggestion and ordered councils held throughout the West so that legates could present the tradition of the Western Church.

[2] During the council, a letter by Pope Agatho was read, which asserted the traditional belief of the Church that Christ was of two wills, divine and human.