Empress mother of Constantine the Great. She was a native of Bithynia, who married the then Roman general Constantius I Chlorus about 270. Constantine was born soon after, and in 293, Constantius was made Caesar, or junior emperor. He divorced Helena to marry co Emperor Maximian’s stepdaughter. Constantine became emperor in 312 after the fateful victory at Milvian Bridge, and Helena was named Augusta, or empress. She converted to Christianity and performed many acts of charity, including building churches in Rome and in the Holy Land. On a pilgrimage to the Holy Land, Helena discovered the True Cross. She is believed to have died in Nicomedia. Her porphyry sarcophagus is in the Vatican Museum. Geoffrey of Monmouth, England, started the legend that Helena was the daughter of the king of Colchester, a tradition no longer upheld. In liturgical art Helena is depicted as an empress, holding a cross.

http://www.catholic.org/saints/saint.php?saint_id=123