Commemoration of the Apparition of the Sign of the Precious Cross Over Jerusalem, in 351 AD (7 May)

The Precious Cross appeared in the sky over Jerusalem on the morning of May 7, 351 during the reign of the emperor Constantius, the son of Saint Constantine (May 21).
At that time the heresy of Arianism, which taught that Christ was merely a creature and not God, was causing great turmoil and division throughout the Empire. Even after the First Ecumenical Council at Nicea in 325, many people were drawn to this false teaching, and the Orthodox found themselves in the minority in many places.
Constantius, the ruler of the eastern part of the Empire, was a fervent supporter of Arianism. His brothers Constantine II and Constans, who were pious Orthodox Christians, ruled in the west. They were both killed in separate battles around 350, leaving Constantius as sole ruler. Also in 350, Saint Cyril (March 18) became Patriarch of Jerusalem and began his zealous struggle against Arianism.
In May of 351 a luminous Cross appeared over Jerusalem, stretching from Golgotha to the Mount of Olives, a distance of about five and a half miles. The Cross was wide as it was long, and shone more brightly than the sun. Many people left their homes and workplaces to gather in the church and glorify Christ. The historian Sozomen says that this wondrous sign led to the conversion of multitudes of pagans and Jews to Christianity.

A letter from Saint Cyril to the emperor describing this phenomenon, and admonishing him to become Orthodox, has been preserved. The apparition of the Cross remained over the city for a whole week.
The vision of the Cross over Jerusalem strengthened the Orthodox faithful and contributed to the return of many Arians to the Church. It is also a reminder of the awesome Second Coming of Christ, when “the sign of the Son of man shall appear in heaven” (Matthew 24:30).
On this day in the year 351, not long after Cyril had succeeded Maximus as Archbishop of Jerusalem, during the reign of Constantius, the son of Saint Constantine the Great, on the day of Pentecost, the sign of the Cross appeared over Jerusalem. Saint Cyril, in his letter to the Emperor Constantius, says, “At about the third hour of the day, an enormous Cross, formed of light, appeared in the heaven above holy Golgotha and reaching to the holy Mount of Olives, being seen not by one or two only, but manifest with perfect clarity to the whole multitude of the city; not, as one might suppose, rushing swiftly past in fancy, but seen openly above the earth many hours in plain sight, and overcoming the beams of the sun with its dazzling rays” (PG 33:1 16q).
During the time of St. Constantine’s son, Emperor Constantius, and Patriarch Cyril of Jerusalem, the Honorable Cross appeared about 9:00 a.m. stretching from Golgotha to above the Mount of Olives. This Cross was brighter than the sun and more beautiful than the most beautiful rainbow. All the people, both believing and unbelieving, left their work and observed this heavenly sign in fear and amazement. Many unbelievers converted to the Christian Faith, and many Arian heretics abandoned their evil heresy and returned to Orthodoxy. About this sign, Patriarch Cyril wrote a letter to Emperor Constantius, who had inclinations toward Arianism. This occurred on May 7, 357 A.D. Thus, even on this occasion it was demonstrated that the Christian Faith is not worldly theorizing, according to the sensual understanding of man. Rather it is God’s power, demonstrated through numerous miracles and signs.
Apolytikion of Appearance of the Sign of the Cross
First Tone
The image of Thy Cross at this time shone brighter than the sun, when Thou didst spread it out from the holy Mount of Olives to Calvary; and in making plain Thy might which is therein, O Saviour Thou didst also thereby strengthen the faithful. Keep us always in peace, by the intercessions of the Theotokos, O Christ our God, and save us.
Kontakion of Appearance of the Sign of the Cross
Fourth Tone
Making its rays to shine above in the heavens, the spotless Cross dawned on the earth, bright with splendour; for it had opened Heaven, which was shut of old. Granted the effulgence of its divine operation, we are surely guided to the unwaning resplendence. In battles we possess it as a true weapon of peace and a trophy invincible.
Source: goarch.org / oca.org / westserbdio.org