In the Christian liturgical calendar, there are several different Feasts of the Cross, all of which commemorate the cross used in the crucifixion of Jesus. Unlike Good Friday, which is dedicated to the passion of Christ and the crucifixion, these feast days celebrate the cross itself, as the sign of salvation. In Roman Catholicism, Eastern Catholicism, Eastern Orthodoxy, Lutheran and Anglicanism the most common day of commemoration is 14 September.

In English, the feast is called The Exaltation of the Holy Cross in the official translation of the Roman Missal, while the 1973 translation called it The Triumph of the Cross. In some parts of the Anglican Communion the feast is called Holy Cross Day, a name also used by Lutherans. The celebration is also sometimes called Holy Rood Day.
The Feast of the Exaltation of the Holy Cross, celebrated every year on 14 September, recalls three events:

The finding of the True Cross by Saint Helena.
The dedication of churches built by Emperor Constantine on the site of the Holy Sepulchre and Mount Calvary.
The restoration of the True Cross to Jerusalem in AD 629 by the Byzantine emperor Heraclius, after it had fallen into the hands of the Persian Emperor Chosroes II in the AD 614 Sasanian conquest of Jerusalem.
Under Emperor Constantine, around AD 327, Bishop Macarius of Jerusalem caused excavations to be made in order to ascertain the location of Calvary as well as that of the Holy Sepulchre. It was in the course of these excavations that the wood of the cross was recovered. It was determined by Macarius to be authentic (the crosses of the two thieves were also recovered) and for it Constantine built the Basilica of the Holy Sepulchre.

The feast was observed in Rome before the end of the seventh century. However, the earliest recorded commemoration of 14 September as the feast day on a Western calendar is from the 7th century A.D.

In the Gallican usage, beginning about the seventh century, the Feast of the Cross was celebrated on 3 May, and called "Crouchmas" (for "Cross Mass") or "Roodmas". When the Gallican and Roman practices were combined, the September date was assigned to commemorating the rescue of the cross from the Sassanid Persians, and the May date was kept as the Finding of the Holy Cross or Invention of the True Cross to commemorate the finding. ("Invention" is a rendering of the Latin term inventio meaning "discovery".) Pope John XXIII removed this feast in 1960, so that the General Roman Calendar now celebrates both the finding and the exaltation of the Holy Cross on 14 September, although some Latin American countries and Mexico still celebrate the feast of the finding on 3 May. Some communities which celebrate the liturgy in the extraordinary form of the Roman Rite also observe the feast of the finding of the Holy Cross on 3 May.
14 September (Church of England)
13 September (Church of the East)