Emperor, born Illyria, died 311. He was an illiterate shepherd, who married the daughter of Diocletian and was adopted by him. In 293 he was made Caesar, receiving the Danubian territories, and succeeding Diocletian as Emperor of the East, 305. He is responsible for the violent persecution of Christianity begun by his father-in-law, 303, which terminated, 311, when he was menaced by Constantine and Maxentius.