page_title: List of Roman wars and battles
section_title: 4th century
hierarchical_section_title: List of Roman wars and battles / 4th century
caption_attribution_description: English: historic map of Roman Empire during the first tetrarchy
context_page_description: The following is a List of Roman wars and battles fought by the ancient Roman Kingdom, Roman Republic and Roman Empire, organized by date.
context_section_description: The 4th century begins with civil war resulting in the ascendancy of Constantine I, then, after his death, wars with Persia and Germanic tribes, punctuated frequently with more civil wars.
  Civil Wars of the Tetrarchy (306–324)
  312 –
  Battle of Turin – Constantine I defeats forces loyal to Maxentius.
  Battle of Verona – Constantine I defeats more forces loyal to Maxentius.
  28 October – Battle of Milvian Bridge – Constantine I defeats Maxentius and takes control of Italy.
  313, 30 April – Battle of Tzirallum – In the eastern part of the Empire, the forces of Licinius defeat Maximinus.
  314, 8 October – Battle of Cibalae – Constantine defeats Licinius
  316 or 317 – Battle of Mardia – Constantine again defeats Licinius, who cedes Illyricum to Constantine.
  324 –
  3 July – Battle of Adrianople – Constantine defeats Licinius, who flees to Byzantium
  July – Battle of the Hellespont – Flavius Julius Crispus, son of Constantine, defeats the naval forces of Licinius
  18 September – Battle of Chrysopolis – Constantine decisively defeats Licinius, establishing his sole control over the empire.
  Wars with Persia (344–363)
  344 – Battle of Singara – Emperor Constantius II fights an indecisive battle against King Shapur II of Persia
  359 – Siege of Amida – Sassanids capture Amida from Romans
  363, 29 May – Battle of Ctesiphon – Emperor Julian defeats Shapur II of Persia outside the walls of the Persian capital, but is unable to take the city, and his death leads to an ultimate disaster on the retreat back to Roman territory.
  Civil War (350–353)
  351 – Battle of Mursa Major – Emperor Constantius II defeats the usurper Magnentius
  353 – Battle of Mons Seleucus – Final defeat of Magnentius by Constantius II
  Wars with Alemanni (356–368)
  356 – Battle of Reims – Caesar Julian is defeated by the Alamanni
  357 – Battle of Strasbourg – Julian expels the Alamanni from the Rhineland
  368 – Battle of Solicinium – Romans under Emperor Valentinian I defeat yet another Alamanni incursion.
  Civil War – 366 – Battle of Thyatira – The army of the Roman emperor Valens defeats the usurper Procopius.
  Gothic War (376–382)
  377 – Battle of the Willows – Roman troops fight an inconclusive battle against the Goths
  378 –
  May – Battle of Argentovaria – Western Emperor Gratianus is victorious over the Alamanni, yet again.
  9 August – Battle of Adrianople – Thervings under Fritigern defeat and kill the Eastern Emperor Valens
  380 – Battle of Thessalonica – The new Eastern Emperor, Theodosius I, is also defeated by the Thervings under Fritigern.
  Civil War – 388 – Battle of the Save – Emperor Theodosius I defeats the usurper Magnus Maximus.
  Civil War – 394, 5–6 September – Battle of the Frigidus – Theodosius I defeats and kills the usurper Eugenius and his Frankish magister militum Arbogast.
caption: The Roman Empire under the Tetrarchy, with the territory of Constantius (yellow), Maximian (green), Galerius (pink), and Diocletian (purple)
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