This feast can be traced back to the early Fourth Century when St. Helena, mother of the Emperor Constantine set out to reclaim the Holy Land. She sought out the various sites from the life of Christ and reclaimed them. She razed the second-century Temple of Aphrodite, which tradition held was built over the Savior’s tomb, and her son built the Basilica of the Holy Sepulcher on that spot. During the excavation, workers found three crosses. Legend has it that the one on which Jesus died was identified when its touch healed a dying woman.

After its discovery, the Cross became an item of devotion. Some accounts would recall that toward the end of the Fourth Century, the wood of the Cross discovered by St. Helena would be venerated on Good Friday in Jerusalem. According to an eyewitness, the wood was taken out of its silver container and placed on a table together with the inscription Pilate ordered placed above Jesus’ head: Then “all the people pass through one by one; all of them bow down, touching the cross and the inscription, first with their foreheads, then with their eyes; and, after kissing the cross, they move on.”

The Basilica of the Holy Sepulcher, where the Relic is enthroned, was dedicated on 13 September 335. Legend would say that on the following day, Christ’s Cross was brought outside the newly built church for the faithful to venerate. Thus, the first showing, or Exaltation of the Holy Cross, might have occurred on 14 September 335. Over the next three centuries, because liturgical celebrations were not widely centralized, the Feast of the Exaltation of the Holy Cross was likely celebrated annually in Jerusalem and varied in other ecclesiastical jurisdictions.

In 614, the Persians invaded Jerusalem and took the True Cross as a trophy. The Persians, primarily followers of the ancient religion of Zoroastrianism, were not Christians. Allowing the Holy Cross to remain in their possession was seen as sacrilegious. Eight years later, in 622, Eastern Roman Emperor Heraclius initiated military campaigns to recapture Jerusalem and the True Cross. Finally, in 628, he triumphed, and the following year, Emperor Heraclius entered Jerusalem with the True Cross, restoring it to the Church of the Holy Sepulchre. After that, the Feast of the Holy Cross became a universal celebration within the Church, starting in Rome and subsequently spreading throughout the entire empire, and has been celebrated annually on September 14 ever since.