On September 27 Christians of the Byzantine Rite celebrate the feast of the Exaltation of the Cross

The feast is originated from the consecration of the Church of the Resurrection of the Lord built by St. Constantine the Great on the Mount of Golgotha in Jerusalem. The church was consecrated at the time of Bishop Makarius of Jerusalem on 13 September, 335. On 14 September the True Cross was ceremonially exalted.

Christians of the Byzantine Rite, on 27 September, celebrate the feast of the Exaltation of the Cross or the Holy Cross Day. The holy day is one of the 12 great feasts of the Eastern Church. The Feast of the Exaltation has a one-day Forefeast and an eight-day Afterfeast.  According to historians, the establishment of the festival was based, primarily, on two events, the finding in the 4th century of the Cross, on which Jesus Christ was crucified and return of the cross from Persia to Jerusalem in the 7th century.

The word "exaltation" means a celebratory ritual of veneration and glorification of the Cross of Christ.

The Christian tradition includes several different legends about the finding of the True Cross. Three of them ascribe the finding of the Cross to the mother of Emperor Constantine I, Holy Empress Helena. The True Cross is said to have been discovered in 326. Historians have no information of exaltation of the True Cross right after the discovery.

The feast is originated from the consecration of the Church of the Resurrection of the Lord built by St. Constantine the Great on the Mount of Golgotha in Jerusalem. The church was consecrated at the time of Bishop Makarius of Jerusalem on 13 September, 335. On 14 September the True Cross was ceremonially exalted.

In 614, the cross was carried away from the church by the Persians, and remained missing until it was recaptured by the Byzantine Emperor Heraclius in 628. The second ceremonial exaltation of the True Cross in Jerusalem also took place on 14 September.
As the feast commemorated Christ's Crucifixion and death and was equaled to the Great Friday, it became a tradition to fast on that day.

Fr. Yulian Katrii in his book "Know your Rite" notes that the Greek Church celebrates the feast on 6 March and the Roman Catholic Church celebrated it on 3 May, but during the reformation of the feasts under Pope John XXIII in 1960, the feast was deleted from the Church calendar.

The feast is known for the ceremonial veneration of the Cross during the rite of exaltation or raising thereof during the matins. There are various rites of exaltation of the Cross in the Eastern Church, particularly, the rite of St. Athanasius on Athos, the rite of the Mount Sinai, the Constantinople rite. In Rus, the rite is mentioned in the 13th century. The Council of 1276 allowed the exaltation in all Churches.