Remembrance of the Appearance in the Heavens of the Cross of the Lord at Jerusalem (351): After the death of the first Christian emperor, Constantine the Great, the imperial throne was occupied by his son Constantius, who inclined towards the heresy of Arius, which denied the one selfsame essence of the Son of God with the Father. In the reaffirming of holy Orthodoxy, the Lord manifest at Jerusalem a wondrous sign. On the day of Holy Pentecost, 7 May 351, at the third hour of the morning in the heavens there appeared the image of the equal-proportioned Cross of the Lord, shining with an inexpressible light, and brighter than the light of the sun. All the people were eye-witness to this, and they were struck with great dread and amazement.
The appearance of the Sign of the Cross began over holy Mount Golgotha, whereupon it was that the Lord had been crucified, and it reached to the Mount of Olives, extending from Golgotha a distance of 15 stadia. The Sign was transfused with all the colours of the rainbow and it caught the sight of all the people. Many of the people, leaving off from whatever they were doing, went outside the houses and with awe stood contemplating the wondrous sign. Then a numerous throng of the people of Jerusalem with trembling and joy hastened to the holy Church of the Resurrection.
The holy Jerusalem Patriarch Cyril (350-387) advised the emissary of the emperor Constantius about this miraculous occurrence of the appearance of the Sign of the Cross, and he urged him to return to the Orthodox faith. And Sozomen, an historian of the Ancient Church, likewise testifies, that through this appearance of the Holy Cross many of the Jews and pagan Greeks came to the true faith, repenting in Christ God, and accepted Holy Baptism.