Nicene and Post-Nicene Fathers, Ser. II, Vol I:
The Life of Constantine with Orations of Constantine and Eusebius.: Chapter XXXII

Chapter XXXII.—How Constantine received Instruction, and read the Sacred Scriptures.

These things were done shortly afterwards. But at the time above specified, being struck with amazement at the extraordinary vision, and resolving to worship no other God save Him who had appeared to him, he sent for those who were acquainted with the mysteries of His doctrines, and enquired who that God was, and what was intended by the sign of the vision he had seen. They affirmed that He was God, the only begotten Son of the one and only God: that the sign which had appeared was the symbol of immortality, 3116 and the trophy of that victory over death which He had gained in time past when sojourning on earth. They taught him also the causes of His advent, and explained to him the true account of His incarnation. Thus he was instructed in these matters, and was impressed with wonder at the divine manifestation which had been presented to his sight. Comparing, therefore, the heavenly vision with the interpretation given, he found his judgment confirmed; and, in the persuasion that the knowledge of these things had been imparted to him by Divine teaching, he determined thenceforth to devote himself to the reading of the Inspired writings.

Moreover, he made the priests of God his counselors, and deemed it incumbent on him to honor the God who had appeared to him with all devotion. And after this, being fortified by well-grounded hopes in Him, he hastened to quench the threatening fire of tyranny.

Footnotes

Both Socrates (5. 17) and Sozomen (7. 15) relate that symbols of the cross found in a temple of Serapis, on its destruction by Theodosius, were explained by the Christians of the time as symbols of immortality. Cf. also Suidas (ed. Gasiford, 2 (1834), 3398), s. v. Σταυροί; Valesius on Socrates and Sozomen; Jablonski, Opuscula, 1, p. 156– . The study of the pre-christian use of the cross is most suggestive. It suggests at least that in some way the passion of our Lord was the realization of some world-principle or “natural Law.”