A Byzantine emperor tried to hold his empire together with a theology of one will
In the 7th century Emperor Heraclius faced provinces split over the nature of Christ, and in Egypt about 30,000 Chalcedonian Greeks lived among some five million Copts who rejected their creed. His answer was a compromise: Christ has two natures but one will. Church councils eventually branded it heresy.
The quarrel went back to the Council of Chalcedon, which defined Christ as having two distinct natures, human and divine, united in one person. Opponents held that there was only one nature: Eutyches pictured the human dissolved in the divine like honey in the sea, while miaphysites spoke of a single united human-divine nature. Each camp accused the other of heresy. For Byzantium this was a strategic problem, since the provinces most sympathetic to the one-nature view, such as Egypt and Syria, were exactly those most exposed to outside enemies.
Patriarch Sergius of Constantinople offered a bridge. If Christ had a single energy, or later a single will, one-nature believers might accept two natures, and some Chalcedonians might accept one will. By 622 Heraclius was promoting this monoenergism in Armenia, and after his war with Persia he used it to win back groups in Syria and Egypt; for a while three of the five great patriarchates taught it. A Palestinian monk, Sophronius, objected that unity was being bought with doctrinal compromise, and once he became Patriarch of Jerusalem in 634 he denounced the idea as disguised monophysitism.
Sergius asked Pope Honorius I to endorse silence on the question, and in 635 Honorius agreed that discussion should stop and that Christ had one will, reasoning that he took on human nature as it was before Adam's fall. When monoenergism lost support, the emperor issued the Ecthesis in 638, banning talk of energies and declaring two natures with one will. Supporters said this did not deny Christ human volition, only that it could never oppose the divine, but critics read it as erasing it.
The compromise collapsed. The Lateran Council of 649 and the Third Council of Constantinople in 680 to 681 condemned it, affirming two wills, the view now standard across major churches. The idea never entirely vanished, though: some modern Protestant philosophers, including William Lane Craig and J. P. Moreland, still defend a form of it.
Source: Monothelitism
