||This article appears to contradict the article Monothelitism. (February 2011)
Monoenergism is a Christian heresy related to and often paired with Monophysitism.
In the 7th century, the Byzantine Emperor Heraclius attempted to solve the schism between Chalcedonians and Monophysites, and suggested the compromise of Monoenergism. This compromise adopted the Chalcedonian belief that Christ had two natures, but tried to address Monophysite misgivings by the view that Christ had one "energy". The definition of the term "energy" was left deliberately vague. Monoenergism was accepted by the Patriarchs of Constantinople, Antioch, and Alexandria, as well as by the Armenians, though not by the Patriarch of Jerusalem or Pope Honorius I. The lack of support from the Pope led Heraclius to abandon the belief in 638. Instead he declared the doctrine of Monothelitism, though this did not solve the schism either.
Both Monoenergism as well as Monotheletism were condemned as heresies by the Sixth Ecumenical Council, held in Constantinople in 680.