Following Constantine the Great's order to build a church over the traditional site of Christ's crucifixion and burial, clergy consecrated the Church of the Holy Sepulchre and, according to tradition, exhibited fragments of the cross discovered by Helena, Constantine's mother. The event gave rise to the Feast of the Exaltation of the Holy Cross, observed by Eastern and Western churches alike.
When Constantine's mother Helena traveled to Jerusalem in the 320s, she was said to have located, beneath a pagan temple, the wooden cross of the crucifixion along with two others. Distinguishing the true relic from the others reportedly involved touching the pieces to a dying woman, who recovered upon contact with the correct one.
The dedication of the Church of the Holy Sepulchre on this date became an occasion to display the relic publicly, and the anniversary evolved into one of the oldest feasts in Christendom. Fragments purportedly from the cross were later distributed across the Byzantine world, fueling a medieval trade in relics so extensive that skeptics joked enough wood existed to build a ship.
The feast day endures in Catholic, Orthodox, and Oriental Christian calendars, a rare liturgical thread connecting fourth-century Jerusalem to congregations worldwide today.