Lesson VI · About AD 250 to 500

How it ended

The questionDid Roman Britain fall, or fade away?

There was no last battle. Over a century and more, the money, the soldiers and the officials drained away, until around AD 410 the emperor told Britain to look after itself. What came after was not empty.

Carausius and Allectus rule Britain
AD 286 to 296, with his successor Allectus1
Latest coins on the Wall
minted AD 403 to 4063
Honorius refuses
around AD 410

Fits: Primary (KS2)

Long flint walls with round towers by the water, with a tall square stone keep rising behind
Portchester, one of the forts built against raiders from the sea in the late 3rd century. Its walls have been lived inside ever since.Photo: David Martin, CC BY-SA 2.0, via Geograph

The story

In the 3rd century, raiders from across the North Sea, often called Saxon pirates, attacked the south and east coasts. A chain of new forts went up to guard the harbours: the forts of the Saxon Shore. Portchester is the best preserved.2 In London, the port closed around 250, and about 275 a wall was built along the river to shut the town off from the water.1

An emperor of Britain

In about 285, Carausius was put in charge of the Roman fleet in the Channel. Condemned to death by the co-emperor Maximian, he rebelled, with the fleet behind him, and declared himself emperor in Britain.2 He seized London in 286 and minted his own coins there. He and his successor Allectus held it until 296, when Britain was taken back.1

Holding on

In the 4th century Britain was divided into four provinces. Christianity was allowed from 313, and in 314 a bishop of London is recorded. Towers were added to London’s walls around 350 against Saxon raids.1 Across the empire, money was short: the government paid out more than it raised, and inflation hit towns hard. At Wroxeter the baths grew shabby and part of the forum was abandoned early in the 4th century.5

Around 410

Between 400 and 410 the Roman army and officials withdrew. The emperor Honorius refused to defend Britain, and London began to empty.1 No new Roman coins came after that: the latest found on Hadrian’s Wall were minted between 403 and 406.3 Roman soldiers were paid in coin; when new coin stopped coming, so did the pay.

What came after

Nobody sacked Wroxeter. Its great buildings were taken down as they became unsafe, and by the middle of the 5th century the centre was empty, though a small community stayed on by the river crossing.5 At Birdoswald, people built timber halls on the site of the old granaries and lived there, without a break, probably into the 6th century. The soldiers had long been local men; with no empire to pay them, they may have become something like a war band, still thinking of themselves as Roman.4 London was largely empty by about 450. Saxon settlers arrived nearby, but mostly kept away from the old Roman city.1

No single end

How long Roman life went on at five places.

  1. London AD 250 to 410Port closed about 250; walled; emptying from 410.
  2. London after AD 410 to 450Largely empty by about 450.
  3. Wroxeter AD 250 to 410Baths shabby, forum partly left in the 300s.
  4. Wroxeter after AD 410 to 450Centre empty by the mid 400s; a village by the ford.
  5. Housesteads AD 250 to 400Village left; people perhaps moved inside the walls.
  6. Birdoswald AD 250 to 410The same unit for two centuries.
  7. Birdoswald after AD 410 to 520Timber halls, lived in probably into the 500s.
  8. Portchester AD 285 to 410Built about 285 to 290; families inside.
  9. Portchester after AD 410 to 500Sunken huts, a well, ploughed ground in the 400s.
Red: Roman rule. Hatched: life going on after it, with dates that are approximate. Each place ended in its own way and at its own time.

Key words

Saxon Shore
The chain of Roman forts along the south and east coasts, built against raiders from across the North Sea.
Usurper
Someone who seizes power without the right to it. Carausius declared himself emperor in Britain in 286.
Honorius
The western Roman emperor who, around 410, refused to defend Britain any more.
Continuity
Things that carry on through a change. At Birdoswald, people kept living in the fort for about a century after Roman rule.

Check yourself

Try to answer in your head, then open each one.

Why were forts like Portchester built?

To defend the coasts and harbours against raiders, often called Saxon pirates, in the late 3rd century.

Who was Carausius?

The commander of the Roman fleet in the Channel, who rebelled and declared himself emperor in Britain in 286. He and his successor Allectus held London until 296.

What happened around AD 410?

The Roman army and officials had left, and the emperor Honorius refused to defend Britain any more.

Did Roman Britain fall or fade? Give one piece of evidence.

Mostly it faded. Wroxeter was never sacked: its buildings were taken down as they became unsafe. At Birdoswald people lived on in timber halls for a century or so. London was largely empty by about 450.

Go deeper

  • Portchester a shore fort lived in for seventeen centuries
  • Birdoswald the halls built after Rome
  • London walls, a closed port and an emptying city

Sources for this page

Every number on this page comes from one of these. How we check.

Last reviewed 12 November 2026. Spotted a mistake? Tell us.

  1. London Museum. A timeline of Roman London: Londinium from start to end. www.londonmuseum.org.uk/collections/london-stories/timeline-roman-london-londinium/Used for: Londinium: founding, population, the fires, the wall, the provinces and the end. Checked 12 November 2026.
  2. History of Portchester Castle, and Description of Portchester Castle. English Heritage. www.english-heritage.org.uk/visit/places/portchester-castle/history-and-stories/history/Used for: Portchester: date, Carausius, the 20 towers, wall height and life inside the walls. Checked 12 November 2026.
  3. Breeze, D. J. History of Hadrian’s Wall. English Heritage. (Former Chief Inspector of Ancient Monuments for Scotland; co-author of the standard work on the Wall.) www.english-heritage.org.uk/visit/places/hadrians-wall/hadrians-wall-history-and-stories/history/Used for: Hadrian’s Wall: its length, plan, builders, garrisons, changes of plan and the end. Checked 12 November 2026.
  4. Wilmott, T. History of Birdoswald Roman Fort. English Heritage. (Senior Archaeologist, Historic England; excavator of Birdoswald.) www.english-heritage.org.uk/visit/places/birdoswald-roman-fort-hadrians-wall/history-and-stories/history/Used for: Birdoswald: the Turf Wall, the Dacian cohort, and the timber halls after Rome. Checked 12 November 2026.
  5. White, R. H. History of Wroxeter Roman City. English Heritage. (Honorary Research Fellow, University of Birmingham.) www.english-heritage.org.uk/visit/places/wroxeter-roman-city/history/Used for: Wroxeter: the Cornovii, the fortress, the 78-hectare city and its slow end. Checked 12 November 2026.
  6. Crow, J. History of Housesteads Roman Fort. English Heritage. (Professor of Classical Archaeology, University of Edinburgh; author of the English Heritage guide to Housesteads.) www.english-heritage.org.uk/visit/places/housesteads-roman-fort-hadrians-wall/history/Used for: Housesteads: size, date, garrison, the Tungrians and Frisians, and the end of the fort. Checked 12 November 2026.