About “Ecthesis”
The Ecthesis is a letter published in 638 CE by the Byzantine emperor Heraclius. It defined monotheletism as the official form of Christianity within the empire. The letter was written by Heraclius, a Byzantine emperor. It expressed the imperial position on the nature of Christ, emphasizing a single will in Christ. The document was intended to unify the empire's Christian population under a common doctrine. (Summary adapted from Wikipedia, CC BY-SA 4.0.)
Some summaries adapted from Wikipedia, CC BY-SA 4.0.