4th century in Roman Britain

Events from the 4th century in Roman Britain.


  • 301
  • Emperor Diocletian fixes the prices of British woollen goods and beer.
  • 306
  • 25 July – Emperor Constantius Chlorus dies at Eboracum (York), after campaigning against the Picts. His son Constantine the Great is acclaimed as his successor by the troops here.
  • 314
  • The reforms of Diocletian take effect, dividing Britain into four provinces and separating military and civilian government.
  • Establishment of initial Christian hierarchy in Britain.
  • Three British bishops attend the Council of Arles.
  • 343
  • January – Emperor Constans visits Britain, and strengthens northern frontier and Saxon Shore.
  • Construction of Pevensey Fort.
  • 353
  • Roman Emperor Constantius II punishes British supporters of the recently defeated usurper, Magnentius, and suppresses paganism.
  • 355
  • Julian the Apostate placed in charge of Britain and Gaul.
  • 359
  • Julian makes Britain main granary for western Roman army.
  • 360
  • Picts and Irish attack northern frontier.
  • 367
  • The Great Conspiracy: Sustained raids by Picts, Irish, and Saxons. Hadrian's Wall abandoned and military commander Fullofaudes captured or killed.
  • 368
  • Count Theodosius arrives in Britain with a military task-force, restores administration under Governor Civilis and commander Dulcitius.
  • 369
  • Theodosius defeats invaders, builds new watchtowers from Filey to Huntcliff, re-fortifies northern frontier.
  • 382
  • Magnus Maximus defeats the Picts and Scots.
  • 383
  • Maximus usurps control of the Empire, taking troops from Britain and abandoning the forts at Chester and the Pennines.
  • 397
  • Saint Ninian converts the region around Galloway to Christianity.