Women commemorated as saints from the early centuries of Christianity include several martyrs who suffered under the Persecution of Christians in the Roman Empire, such as Agnes of Rome, Saint Cecilia, Agatha of Sicily and Blandina. The passion of Saints Perpetua and Felicity, written by Perpetua during her imprisonment in 203, recounted their martyrdom. The passion is thought to be one of the earliest surviving documents to have been written by a woman in early Christianity. In late Antiquity, Saint Helena was a Christian and consort of Emperor Constantius, and the mother of Emperor Constantine I. Similarly, Saint Monica was a pious Christian and mother of Saint Augustine of Hippo.