“Christ has commanded pastors to be watchful: this concerns us also, and especially must we watch over the purity of the faith, since certain bishops, who do not deserve this name, have lately sought to spoil our confession of belief by new invented expressions. Everyone knows them, since they have come forward openly to injure the Church: such are Cyrus of Alexandria, Sergius of Constantinople, and his followers, Pyrrhus and Paulus. Cyrus eighteen years ago taught in Alexandria One Operation in Christ, and published from the pulpit nine heads of doctrine. Sergius approved this, issued somewhat later the Ecthesis under the name of the emperor Heraclius, and taught One Will and One Operation, which leads to One Nature of Christ. The Fathers distinctly taught that Operation answers to Nature, and whoever has like Operation must likewise be of like Nature. Since then the Fathers teach Two Natures in Christ, it follows that Two Wills and Operations are united without mixture and without division in one and the same Incarnate Word. That both are naturally one thing is not possible. Pope Leo also taught Two Wills, and so holy Scripture indicates. So Christ wrought what belonged to the Godhead corporeally, since He manifested it through His flesh animated by a reasonable soul; but what belonged to the Manhood, He wrought by the Godhead, since He took upon Him freely for our sake human weaknesses, that is, sufferings, but without sin. Cyrus, in issuing his nine heads of doctrine, Sergius, in issuing the Ecthesis, contradicted the doctrine of Leo, and of the Council of Chalcedon. But Pyrrhus and Paulus spread the error more widely; in particular, Pyrrhus by threats and flatteries seduced many bishops to subscribe his impiety. When he had afterwards come to shame, he came hither and presented to our Holy See a writing in which he anathematised his former error. But he returned as a dog to his vomit, and was therefore rightly deposed. But Paulus went even beyond his predecessor; he confirmed the Ecthesis, and contradicted the true doctrine.