Diocletian

Timeline

1. c. 244–283Salona · DalmatiaOf Illyrian lower-class origins, he rose through the ranks of the army, serving under emperors such as Aurelian and Probus, and was known for military ability and caution.
2. 284–292Nicomedia · BithyniaProclaimed emperor by the army in 284, he defeated rivals and stabilized the political situation; he carried out administrative partitioning, army expansion, the Edict on Maximum Prices, and tax reforms, strengthening central authority.
3. 293–305Roman Empire · Mediterranean worldIn 293 he established the Tetrarchy, taking the title of Eastern Augustus with Maximian as Western Augustus, and elevating Galerius and Constantius to Caesar; from 303 to 305 he launched the Great Persecution of Christians.
4. 305–311Split · DalmatiaIn 305 he abdicated together with Maximian, one of the few emperors in Roman history to voluntarily relinquish power; in his later years he witnessed the collapse of the Tetrarchic system and died in Dalmatia in 311.