Flavia Julia Helena[a] (AD 246/248 – 330), also known as Helena of Constantinople and in Christianity as Saint Helena,[b] was a Greek Augusta of the Roman Empire and mother of Emperor Constantine the Great as well as a Canonized saint in both Catholic and Orthodox Churches for her pivotal role in the spread of Christianity. She was born in the lower classes traditionally in the city of Drepanon, Bithynia, in Asia Minor, which was renamed Helenopolis.
Helena ranks as an important figure in the history of Christianity. In her final years, she made a religious tour of Syria Palaestina and Jerusalem, during which ancient tradition claims that she discovered the True Cross. The Eastern Orthodox Church, Catholic Church, Oriental Orthodox Churches, Anglican Communion, and the Lutheran Church revere her as a saint.
 
Helena died around 330, with her son at her side. She was buried in the Mausoleum of Helena, outside Rome on the Via Labicana. Her sarcophagus is on display in the Pio-Clementine Vatican Museum, next to the sarcophagus of her granddaughter Constantina (Saint Constance); however, in 1154 her remains were replaced in the sarcophagus with the remains of Pope Anastasius IV, and Helena's remains were moved to Santa Maria in Ara Coeli.  Socrates of Constantinople, Nikephoros Kallistos Xanthopoulos and other historians claimed that Helena's body was removed from her sarcophagus two years after her death and transported to the Church of the Holy Apostles in Constantinople.  Stephen of Novgorod describes the tomb of Constantine and Helen and its location as being east of the sanctuary.