DiocletianCaesar Gaius Aurelius Valerius Diocletianus Augustus 244 CE to 311 CE - Diocletian came from a lower class family. By rising through the military, he became a General. After the sudden deaths of emperor Carus and his son Numerian, Diocletian was declared emperor by the Roman Army. During his rule he split the Roman Empire into four divisions and assigned co-emperors to rule them.