18 August - Hélène is said to have been born in Drépanum in the province of Bithynie in Asia Minor. Constance Chlore, a Roman general, married her in 272. Their marriage gave birth to Constantine in 275.

Constance Chlore, who became Caesar, probably already married Theodora, daughter of Augustus Maximian. Hélène did not marry - or did not remarry - and was then living in the shadows. After the advent of Constantine I in 306, Hélène returned to public life and stayed at the imperial court in Trier. From 312 onwards, she lives mainly in Rome, where she converts to Christianity and carries out an active apostolate of the new faith. Known for having organized the first restoration of the Christian holy places in Jerusalem, she went to the Holy Land around 326-328. There she founded the Church of the Pater Noster and the Basilica of the Nativity, and discovered in Jerusalem the holy relics of the Passion of Christ, giving an important impetus to pilgrimages to the Holy Land and to the restoration of the sites.

Hélène's most important legendary discovery was the invention of the True Cross on the site of the Holy Sepulchre. She died around 330, with her son at her side. Constantine had his residence, the Sessorium Palace, transformed into a church, the Basilica of the Holy Cross of Jerusalem.