In 482, the Emperor Zeno and Patriarch Acacius of Constantinople co-wrote a document which would become known as the Henotikon, in order to unite the fracturing empire. The document reaffirmed the Nicean Creed, endorsed the Council of Ephesus (431), absolutely condemned both Nestorius and Eutyches, defined Christ as Jesus, the Logos made flesh, who is: "...one and not two; consubstantial with the Father as touching the Godhead, and consubstantial with us as touching the manhood... one and the same Son." (without specifying whether this oneness referred to the nature or person of Christ), and also said: "...and we anathematize every person who has thought or thinks otherwise, either now or at any time, whether at Chalcedon or at any other synod."
This document was signed by Patriarch Matyrius of Jerusalem in order to attain peace among the non-Chalcedonians and Chalcedonians in Palestine, even though he had previously had Chalcedonian sympathies; and had been tonsured a monk at the Lavra of Euthymius.
The Chalcedonian Patriarch of Antioch Calendion refused to sign the Henotikon and supported the rebellion of the Roman general Flavius Illus against the Emperor. Emperor Zeno crushed the rebellion in 484, and recalled the exiled non-Chalcedonian Patriarch Peter the Fuller, who signed the Henotikon and was restored to his see.
The Chalcedonian Patriarch of Alexandria John Talaia refused to sign the Henotikon, and was expelled from his see by the Emperor who recalled the exiled non-Chalcedonian Patriarch Peter Mongus, who signed the Henotikon and was restored to his see. Talaia fled to Italy and sought refuge with Pope Simplicius of Rome. This pope, or his successor Felix III, refused to recognize Mongus and defended Talaia's rights in two letters to Acacius of Constantinople. Felix sent two of his legates to Constantinople in 484, where they participated in a liturgy where Acacius commemorated Peter Mongus as Patriarch of Alexandria in the diptychs. The legates returned to Rome, reported this to the Pope, who subsequently excommunicated Acacius and the rest of the Eastern Churches, resulting in the thirty-five year Acacian schism.
The only clergy in the East who retained communion with Rome, during this period were the so-called Akoimetoi (or "Sleepless Monks"). They earned their name from their defining religious practice: maintaining uninterrupted, 24-hour prayer and divine service. To achieve continuous prayer without sleep deprivation, the community divided its monks into three alternating shifts or choirs (turmae), organized by language (typically Greek, Latin, and Syriac). As soon as one choir finished its service, the next immediately took over, ensuring the liturgy never ceased. The main stronghold of the monastic brotherhood was at the Monastery of Eirenaion on the Asiatic shore of the Bosphorus. In 484, the Akoimetoi broke communion with Patriarch Acacius and placed themselves under the jurisdiction of the pope of Rome. Legend says that an Akoimetoi monk secretly pinned the papal decree of excommunication onto the back of Acacius's robes during a divine liturgy in the Hagia Sophia. During the entire thirty-five year period of the Acacian schism the Akoimetoi acted as the Pope's spies and agents in Constantinople. Their downfall came about when they refused to acknowledge the Emperor Justinian's 'Theopaschite formula' ("One of the Trinity suffered in the flesh"), and in 534 they were condemned as Nestorians by Pope John II of Rome. The Akoimetoi continued to subsist at their monastery for decades after their official condemnation, outside of communion with everyone.