The proclamations of the Council of Nicaea did not end the Arian heresy, but in fact, began the real drama of the fourth century; a fierce battle in the Church.
For two years after the Council, the Emperor’s sister, Constantina, pleaded for the release of Bishop Eusebius from exile; for his disagreement with the Council. Her former Bishop in Nicomedia, she held Eusebius in high regard. He had now recanted and documented his submission in writing so he was released by Constantine along with the other dissenting bishops and the heretic Arius.
Subsequently, Eusebius gained high favor with Constantine and was reinstated as Bishop of Nicomedia (another first in the Emperor's control of the Church).
With this new backing, Eusebius reneged on his “coerced” acceptance of the Nicene Creed and began a campaign against it. He did not declare himself an Arian, nor challenge the refutation of the entire Arian heresy; he only declared specifically against the doctrine of consubstantiality. This started a new heresy that had staying power and widespread adoption because it had the essential ingredient of Emperor-based power.
Eusebius had been a student of the martyr Lucien at Antioch to whom he attributed his resolute position. He obtained the backing of a large number of prelates, also former students of Lucian, that the Nicene Council was a misguided attack against their holy and learned teacher, Lucien.
Over the next three decades more than a dozen synods were held that attacked the word homoousion (consubstantial) in the creed and produced variations or totally different creeds.
In early Greek philosophy, words like ousia (essence), hypostasis (substance), physis (nature), and hyposopon (person) bore a variety of meanings. The various creeds mentioned above employed word games to eliminate homoousion. The word homoiousion (like in substance) was the favorite Semi-Arian word.
Eusebius did not limit his campaign to theological arguments, but set out to put down anyone that supported the Nicene Creed’s word homoousion. He was ferocious in his tactics.
First, his campaign specifically attacked Bishop Eustathius of Antioch, the Nicene Council’s leader, by convening a Synod at Antioch to depose him. Coincidentally, Bishop Eustathius had antagonized the other Bishop Eusebius (of Caesarea) by criticizing his publication of his rationalization (obfuscation) of the Nicene Creed. This became a contentious adversarial debate in writing.
Meanwhile, and apparently mysteriously, the Emperor was informed that Bishop Eustathius had made disparaging remarks against Constantine's mother, Helena (St. Helen, a great devotee of Lucian).
For whichever reason, to avoid another doctrinal conflict or because of the rumors of the disparaging remarks, the Emperor deposed and exiled Eustathius; (another Imperial action without Ecclesiastical authority).
Next, Eusebius took on Athanasius, the champion of orthodoxy at Nicaea; who was now the Patriarch of Alexandria, after the death of Alexander. Solidly backed by 100 bishops, Athanasius was strong, but his Church was infested with Arians, who only weakly recanted the heresy after the Nicene Council.
Eusebius wrote to Athanasius asking him to reinstate Arius, Also, he induced the Emperor to write demanding that the Patriarch establish peace with the Arians, if he didn't want to be deposed. Athanasius responded negatively to the Emperor while politely explaining his position.
Having failed in this approach, Eusebius colluded with the Mellitus schism (which happened to be going on at that time in Egypt) to trump up charges against Athanasius. The Patriarch was taken to court, but was exonerated.
Meanwhile, the Emperor had called for a Council of Bishops in Jerusalem to dedicate the new Church of the Holy Sepulcher, at Calvary, where Constantine’s mother, Helena, apparently had discovered Jesus’ cross.
Still determined to destroy Athanasius, Eusebius convinced the Emperor that, to establish religious peace, the bishops on their way to the Jerusalem Council should convene in a Synod at Tyre. He noted that although Arius had recanted his heresy in writing, Athanasius would not reinstate him.
At the Tyre Synod, bishops backing Athanasius were not allowed to participate. Seeing that the Synod was stacked against him, Athanasius, and his Egyptian bishops left and went directly to Constantinople to protest to the Emperor. After Athanasius left Tyre, he was deposed by those bishops at the Synod backing Eusebius.
In response to Athanasius’ plea, the Emperor directed that the Tyre Synod reconvene at Constantinople where he would adjudicate. Instead of going, Eusebius went on to the Jerusalem Council, but sent a delegation of bishops to confront Athanasius, led by Eusebius of Caesarea. At Constantinople the delegation from the Tyre Council brought new charges against Athanasius which had nothing to do with the religious debate, but had to do with alleged violations against the Empire. These allegations enraged the Emperor so much that, without hearing the defense, he exiled Athanasius to Gaul.
With Athanasius out of the way, Eusebius’s next plan was to have Arius himself reinstated. The other bishops who were already gathered at Jerusalem welcomed Eusebius, and in Council, they accepted Arius back into communion. Based on this, Eusebius convinced the Emperor to reinstate Arius. The date was set for Arius to be solemnly restored into the Catholic community at the Cathedral of Constantinople. Mysteriously, Arius died the night before the ceremony.
For the next two years, until the Emperor Constantine died, the Emperor did Eusebius’ bidding, Eusebius and his bishops were busy identifying opposing bishops and having them deposed. Deposing Marcellus, Metropolitan of Ankara, was a major victory for Eusebius, He had been a major opponent at Nicaea and at the Tyre Synod, where he refused to condemn Athanasius. He also had sent a book to the Emperor critical of Eusebius.
In the same year as that victory, Eusebius had a moderate disappointment. An orthodox, Paul, was named Bishop of the capital city of Constantinople. He had to postpone that problem into a future agenda.
By 337 AD, when Constantine was baptized by Eusebius on his death bed, the Eastern Church had a large number of Arian or Semi-Arian bishops occupying the Sees of the many deposed orthodox bishops.