He said that about noon, when the day was already beginning to decline, he saw with his own eyes the trophy of a cross of light in the heavens, above the sun, and bearing the inscription, By This Conquer. At this sight he himself was struck with amazement, and his whole army also, which followed him on this expedition, and witnessed the miracle.

He said, moreover, that he doubted within himself what the import of this apparition could be. And while he continued to ponder its meaning, night suddenly came on; then in his sleep the Christ of God appeared to him with the same sign which he had seen in the heavens, and commanded him to make a likeness of that sign which he had seen in the heavens, and to use it as a safeguard in all engagements with his enemies.

At dawn of day he arose, and communicated the marvel to his friends: and then, calling together the workers in gold and precious stones, he sat in the midst of them, and described to them the figure of the sign he had seen, bidding them represent it in gold and precious stones. The standard of the Cross, the Labarum, went before his army that day at the Milvian Bridge, and within months the Edict of Milan gave the Church of Christ her freedom throughout the Roman world.

When the day appointed for the council had come, on which the questions of the Faith were to be settled, the members assembled in the principal hall of the palace. As soon as all were seated in due order, and silence was secured, the Emperor entered, in the splendor of his imperial robes; but his appearance was marked by modesty rather than by pride. He took his seat on a low chair of gold prepared for him, and a signal was given that the bishops might also be seated.

Then a certain Father of the synod, the senior Eustathius of Antioch in the Eastern tradition, rose and addressed the Emperor in a brief speech, returning thanks to God on his behalf. Constantine then spoke in Latin, an interpreter rendering his words into Greek for those of the Fathers who needed it. He said that the work which the Council had to do was the work of God, and that whatever was decreed by them as accordant with the Holy Spirit he himself would account ratified and approved.

Then the bishops began to dispute the question of the Arian doctrine. The disputes lasted for many days. Finally, after the language of the Symbol had been carefully framed, all the bishops subscribed it; only Arius, and two others with him, refused, and were deposed. The Emperor declared that all the council had agreed should have the force of law throughout the empire, and as he closed the council in person, he passed among the seated bishops, and is said to have kissed the scars of those who had been confessors in the recent persecutions, before he kissed their bishop's rings.