Its story
In the early 7th century the Byzantine Empire, threatened by Persians and then Arabs, needed internal unity, and the split between Chalcedonians and miaphysites weakened its eastern provinces. Patriarch Sergius of Constantinople, with Emperor Heraclius, proposed a compromise: accept Chalcedon's two natures but affirm a single energy or operation in Christ. In 633 Patriarch Cyrus of Alexandria achieved a union with Egyptian miaphysites on this basis.
The monk Sophronius, later patriarch of Jerusalem, protested. To avoid the debate, Sergius forbade talk of one or two energies and, with Heraclius' Ekthesis (638), moved to affirming one will in Christ. Pope Honorius I, consulted by Sergius, had written in terms that seemed to accept 'one will', which had consequences later. In 648 Emperor Constans II issued the Typos, forbidding all discussion of the matter.
Maximus the Confessor was the opposition's chief theologian. He argued that will belongs to nature: if Christ is fully human, he has a real human will, which in Gethsemane ('not my will, but yours be done') freely submits to the divine will; what is not assumed is not healed. The Lateran Synod (649), under Pope Martin I and with Maximus taking part, condemned monothelitism. Martin was arrested and died in exile (655); Maximus had his tongue and right hand cut off and died in exile in 662.
The Third Council of Constantinople (680–681), the sixth ecumenical council, defined two natural wills and two operations in Christ, not opposed, the human subject to the divine, and anathematized Sergius, Cyrus and also Pope Honorius. This condemnation of a pope has been debated over the centuries, especially in connection with papal infallibility at Vatican I. Monothelitism revived briefly under Philippicus (711–713) and then disappeared.