Eusebius of Caesarea (c. AD 263–339) also called Eusebius Pamphili, was a Roman historian. Little is known of Eusebius since much of his work is lost, and no copies remain of a a biography of Eusebius by Acacius. He became the Bishop of Caesarea in Palestine about the year 314. Together with Pamphilus, he was a scholar of the Biblical canon. He wrote Demonstrations of the Gospel, Preparations for the Gospel, and On Discrepancies between the Gospels, studies of the Biblical text. As "Father of Church History" he produced the Ecclesiastical History, On the Life of Pamphilus, the Chronicle and On the Martyrs.Life of Constantine is primary source material on the life of Constantine, persecution of Christians, and Constantine’s conversion to Christianity.