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Bust of Diocletian. Arkeoloji Müzesi, İstanbul (Turkey). Photo Marco Prins.
Bust of Diocletian (Arkeoloji Müzesi, İstanbul)
Diocletian: emperor of the Roman world (284-305).


  • 22 December 245: Diocles 
  • 20 November 284: Imperator Caesar, Gaius Aurelius Valerius Diocletianus Augustus 
  • 1 April 286: Imperator Caesar Gaius Aurelius Valerius Diocletianus Augustus Iovius 
  • 1 May 305: resigned
  • 3 December 313: natural death
co-emperor of Maximianus; ruled in the east

Successor of: Numerianus


Early career:

  • 245 Born in Dalmatia (near Salonae?)
  • Military service in Moesia
  • 283 Consul suffectus (?)

Main deeds:

  • 284 Proclaimed as emperor by the troops after the death of Numerianus, son of Carus
  • 285 Consul suffectus II; battle of the Margus; dead of Carinus; Diocletianus is recognized by the Senate; visit to Rome; war against the Sarmatians; accepts the titles Germanicus Maximus and Sarmaticus Maximus; Diocletianus appoints Maximianus as his caesar
  • 286 Maximianus made co-ruler; Diocletian accepts the title Iovius
  • 287 Consul III (with Maximianus); intervention in Armenia; Maximianus fights against the Germanic tribes; Diocletian accepts the title Germanicus Maximus II and III
  • 288 Launches an attack on the Germanic tribes, from Raetia; meeting with Maximianus; accepts the title Germanicus Maximus IV
  • 289 War against the Sarmatians; accepts the title Sarmaticus Maximus II 
  • 290 Consul IV (with Maximianus III)
  • 290/291 Meeting with Maximianus in Milan
  • 292 Maximianus fights against the Alamans
  • 293 Consul V (with Maximianus IV); First Tetrarchy: Galerius and Constantius I Chlorus proclaimed caesares; Diocletian's daughter Galeria Valeria marries to Galerius; all four men accept the title Germanicus Maximus, Diocletian for the fifth time; in the Sasanian Empire, Bahram II dies, and is succeeded by Bahram III, and Narseh
  • 294 War against the Sarmatians; accepts the title Sarmaticus Maximus III; Decennalia
  • 295 Marriage edict; Galerius fight against the Persians (?); Diocletian accepts the title Persicus Maximus
  • 296 Consul VI (with Constantius II); Diocletian fights against the Carpi; accepts the title Carpicus Maximus and adds Britannicus Maximus after Constantius has reconquered Britain; the Sasanian king Narseh occupies Armenia; insurrection of Domitius Domitianus in Egypt
  • 297 Death of Domitianus; he is succeeded by Aurelius Achilleus
  • 297-298 Diocletian suppresses the rising in Egypt; sack of Alexandria
  • 298 Galerius defeats Narseh; end of the Persian war; treaty of Nisibis (Rome gains territory east of the Tigris); Galerius and Diocletian accepts the titles Armeniacus Maximus, Medicus Maximus, Adiabenicus Maximus, and Persicus Maximus II
  • 299 Consul VII (with Maximianus VI); Diocletian in Syria
  • 300 Accepts, after Galerius' successes along the Danube, the title Sarmaticus Maximus IV
  • 301 Monetary reform; edict on Maximum Prizes; accepts, after Constantius' successes along the Rhine, the title Germanicus Maximus VI
  • 302 Edict against the Manichaeans (?)
  • 303 Consul VIII (with Maximianus VII); in the Sasanian Empire, Narseh dies and is succeeded by Hormizd II; brief insurrection of Eugenius in Seleucia; edict against the Christians; Vicennalia in Rome; joint triumph with Maximianus
  • 304 Consul IX (with Maximianus VIII)
  • 305 Diocletian and Maximianus resign; Second Tetrarchy: they are succeeded by Galerius and Constantius I Chlorus, who appoint as caesares Maximinus Daia and Severus II
  • Diocletian settles in Spalato and keeps out of politics; only in 308, as consul X (with Galerius VII), he joins a conference at Carnuntum. He dies in 313.
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Model of Diocletian's palace in Spalato (Split). Museo nazionale della civiltà romana, Roma (Italy). Photo Jona Lendering.
Model of Diocletian's palace in Spalato (Split). Museo nazionale della civiltà romana, Rome

Contemporary events:

  • 301 Gregory the Illuminator converts the Armenians
  • 305 Death of Porphyry


Baths of Diocletian (Rome); Spalato

New legions: I Iovia; I Martia; I Maximiana; I Noricorum; I Pontica; II Flavia Constantia; II Herculia; III Diocletiana; III Herculia; IIII Parthica; V Iovia; V Parthica; VI Herculia; VI Parthica

Succeeded by: Galerius

This brief article has been written to offer background information
to the real articles on Livius.Org. One day, this webpage will be
improved. A list of completed articles can be found here.

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