The empire of the East was gradually sinking in power during this long and quiet reign of Theodosius II.; but the empire of the West was being hurried to its fall by the revolt of the barbarians in every one of its widespread provinces.  Henceforth in the weakness of the two countries Egypt and Rome are wholly separated.  After having influenced one another in politics, in literature, and in religion for seven centuries, they were now as little known to one another as they were before the day when Fabius arrived at Alexandria on an embassy from the senate to Ptolemy Philadelphus.

Theological and political quarrels, under the name of the Homoousian and Arian controversy, had nearly separated Egypt from the rest of the empire during the reigns of Constantius and Valens, but they had been healed by the wisdom of the first Theodosius, who governed Egypt by means of a popular bishop; and the policy which he so wisely began was continued by his successors through weakness.  But in the reign of Marcian (450—­457) the old quarrel again broke out, and, though it was under a new name, it again took the form of a religious controversy.  Cyril, the Bishop of Alexandria, died in the last reign; and as he had succeeded his uncle, so on his death the bishopric fell to Dioscorus, a relation of his own, a man of equal religious violence and of less learning, who differed from him only in the points of doctrine about which he should quarrel with his fellow-Christians.  About the same time Eutyches, a priest of Constantinople, had been condemned by his superiors and expelled from the Church for denying the two natures of Christ, and for maintaining that he was truly God, and in no respect a man.  This was the opinion of the Egyptian church, and therefore Dioscorus, the Bishop of Alexandria, who had no right whatever to meddle in the quarrels at Constantinople, yet, acting on the forgotten rule that each bishop’s power extended over all Christendom, undertook of his own authority to absolve Eutyches from his excommunication, and in return to excommunicate the Bishop of Constantinople who had condemned him.  To settle this quarrel, a general council was summoned at Chalcedon; and there six hundred and thirty-two bishops met and condemned the faith of Eutyches, and further explained the Nicene creed, to which Eutyches and the Egyptians always appealed.  They excommunicated Eutyches and his patron Dioscorus, who were banished by the emperor; and they elected Proterius to the then vacant bishopric of Alexandria.

In thus condemning the faith of Eutyches, the Greeks were excommunicating the whole of Egypt.  The Egyptian belief in the one nature of Christ, which soon afterwards took the name of the Jacobite faith from one of its popular supporters, might perhaps be distinguished by the microscopic eye of the controversialist from the faith of Eutyches; but they equally fell under the condemnation of the council of Chalcedon.  Egypt was no longer divided in its religious opinions.