- c.250: Born in Drepanon in Bithynia
- c.270: Marriage to Constantius, who is about her age
- 272 Birth of Constantine
- 289 Separated from Constantius, who is forced to marry Theodora, a stepdaughter of Maximianus
- 306 Constantine becomes emperor; Helen stays on his court
- 325 Helen proclaimed Augusta
- 326 Helen begins her pilgrimage to the Holy Land
- 329 Death
- Helen was buried in the mausoleum in Rome that Constantine had built for himself, the present Santa Costanza; her sarcophagus is now in the Vatican
In the late fourth century, it was said that Helen had found the True Cross during her visit to Jerusalem; this story is not mentioned in the writings of Eusebius, who, as bishop of Caesarea, must have known it when this really happened. As he does not mention it,the story is probably a legend. However, the visit to Jerusalem and the buidling of the church of the Holy Sepulcher, are uncontested facts.
Since the fifth century, Helen has been venerated as a saint in the Byzantine Empire; her saint's day is 21 May. Her cult spread to the west in the second half of the ninth century, where her saint's day is 18 August. Other honors were that her birthplace, Drepanon in Bithynia, was renamed Helenopolis.