Cyrus of Alexandria
He had been since 620 Bishop of Phasis in Colchis when the Byzantine Emperor Heraclius, in the course of his Persian campaign of 626, consulted him about a plan for bringing the Monophysites (a Christological heresy) of Egypt back to the Church and to the support of the empire. The plan, suggested by Sergius, Patriarch of Constantinople, consisted of confessing the faith of Chalcedon on the two natures of Christ, while practically nullifying it by the admission of one theandric will and operation, eu telèma kai mia energeia. Cyrus hesitated at first, but being assured by Sergius that this formula was opposed to neither the Fathers nor to Chalcedon and was destined to achieve great results, he became a staunch supporter of it, and was, in return, raised by Heraclius to the then vacant see of Alexandria in 630.
Once a patriarch, Cyrus set himself vigorously to effect the desired union. In a synod held at Alexandria, he proposed what is known as the klèrothoria or "Satisfactio", an agreement in nine articles, the seventh of which is a bold assertion of the Monothelite heresy. The Monophysites (Theodosians or Severians) welcomed the agreement but remarked that Chalcedon was coming to them, not they to Chalcedon.
The union thus effected was adroitly exploited, with a view to win over Pope Honorius I to Monothelism. Cyrus attended another synod at Cyprus under Arkadios II, at which he served as moderator and permitted Monothelite opponents to submit their case to the Emperor. When Cyrus received the Emperor's Monothelite response, the Ecthesis, Cyrus signed it in 637. This compromise proved ineffective, and soon fell into discredit under the name of enoosis hydrobatès, contemptuously called the "washy union".
When Caliph Omar's general, Amru, threatened the Prefecture of Egypt, Cyrus was made prefect and entrusted with the conduct of the war. Certain humiliating stipulations, to which he subscribed for the sake of peace, angered his imperial master so much that he was recalled and harshly accused of connivance with the Muslims; however, he was soon restored to his former authority, owing to the impending siege of Alexandria, but could not avert the fall of the great city in 640 and died shortly after.
The first letter is an acceptation of the Ecthesis; in the second Cyrus describes his perplexity between Pope Leo and Sergius; the conversion of the Theodosians is narrated in the third.
The seventh article of the "Satisfactio" — the others are irrelevant — reads thus: "The one and same Christ, the Son, performs the works proper to God and to man by one theandric operation  according to St. Dionysius".
Cyrus' chief opponents, St. Sophronius, died in 637 (Epistola synodica, Mansi, XI, 480), and St. Maximus, died in 662 (Epistola ad Nicandrum; disputatio cum Pyrrho, P.G., XCI, 101, 345), reproached him for falsifying the then much-respected text of Dionysius and substituting for (new). They showed, moreover, the inanity of his claim to the support of the Fathers, and explained how the Divine and human natures of Christ, sometimes styled one, because they belong to the same person and work in perfect harmony, can no more by physically identified than the natures from which they proceed. Historians are not agreed as to how Cyrus came by this error. Some think that he was, from the outset, a Monophysite at heart. Others, with more reason, hold that he was led into error by Sergius and Heraclius.
Cyrus was posthumously condemned as a heretic in the Lateran Council of 649 (Denzinger, Enchiridion, 217, 219) and in 680 at the Third Œcumenical Council of Constantinople (Denzinger, 238; Mansi, XI, 554).
Cyrus of Alexandria