Events which occurred in Alexandria after the Death of Arius. Letter of Constantine the Great to the Church there
The death of Arius did not terminate the doctrinal dispute which he had originated. Those who adhered to his sentiments did not cease from plotting against those who maintained opposite opinions. The people of Alexandria loudly complained of the exile of Athanasius, and offered up supplications for his return; and Antony, the celebrated monk, wrote frequently to the emperor to entreat him to attach no credit to the insinuations of the Melitians, but to reject their accusations as calumnies; yet the emperor was not convinced by these arguments, and wrote to the Alexandrians, accusing them of folly and of disorderly conduct.
He commanded the clergy and the holy virgins to remain quiet, and declared that he would not change his mind nor recall Athanasius, whom, he said, he regarded as an exciter of sedition, justly condemned by the judgment of the Church. He replied to Antony, by stating that he ought not to overlook the decree of the Synod; for even if some few of the bishops, he said, were actuated by ill-will or the desire to oblige others, it scarcely seems credible that so many prudent and excellent bishops could have been impelled by such motives; and, he added, that Athanasius was contumelious and arrogant, and the cause of dissension and sedition.
The enemies of Athanasius accused him the more especially of these crimes, because they knew that the emperor regarded them with peculiar aversion. When he heard that the Church was split into two factions, of which one supported Athanasius and the other John, he was transported with indignation, and exiled John himself. This John had succeeded Melitius, and had, with those who held the same sentiments as himself, been restored to communion and reestablished in the clerical functions by the Synod of Tyre.
His banishment was contrary to the wishes of the enemies of Athanasius, yet it was done, and the decrees of the Synod of Tyre did not benefit John, for the emperor was beyond supplication or petition of any kind with respect to any one who was suspected of stirring up Christian people to sedition or dissension.
Source: Ecclesiastical History (New Advent)