In 482 Emperor Zeno, with the support of Patriarch Acacius of Constantinople, issued an imperial edict called the Henotikon (coming from the Greek word meaning “unity” or “union”), which was designed to bring reconciliation between those who accepted the Council of Chalcedon and those who rejected it. The Henotikon strongly affirmed the first three Ecumenical Councils, avoided any mention of one or two natures in Christ, and anathematized “anyone who has held or holds any other opinion, either now or at any other time, whether at Chalcedon or at any synod whatsoever.”
The Henotikon mollified the moderate Monophysites, who continued to stay in communion with the Chalcedonian Byzantines—for as yet there had been no actual schism in the Church. But it infuriated the Roman Church, since it certainly did place a question mark over the Council of Chalcedon, at which the Tome of their beloved Saint Leo was so influential. In 484 Pope Felix of Rome (r. 483–492) excommunicated all the Churches of the East on account of their acceptance of the Henotikon. This began the so-called Acacian Schism between Rome and the East, which lasted until 518.