THIS DAY IN HISTORY:
Diocletian's Army Declares Him Emperor of Rome (284 CE)
Of humble birth, Diocletian rose through the ranks of the Roman military to become a high-ranking commander. His troops proclaimed him emperor after the death of Numerian, and he became sole ruler when Carinus, Numerian's co-emperor, was murdered by his own officers. Seeking to remove the military from politics, Diocletian established a tetrarchy, or four-ruler system, appointing Maximian, Constantius I, and Galerius as co-rulers and proclaiming them all gods.