Roman Conquest of Britain Summary

  • Last updated on November 11, 2022

The Romans created a new province by subjugating Britain’s Celtic tribes and left their cultural imprint on the island.

Summary of Event

At the beginning of the Christian era, Britannia—the Roman name for England, Wales, and southern Scotland—had an Iron Age culture. Before the sixth century b.c.e., Celtic language and culture had crossed the English Channel from the Continent and, by the time of Julius Caesar, predominated throughout the island. Little is known of the Celts’ history because they were preliterate, and Greek and Roman writers only wrote about them to the extent that they interacted with classical culture. Archaeology allows an estimate of their development. Tribal kingdoms dominated by warrior aristocracies fought incessantly. Possessing rich farmland, engaging in frequent trade with their Celtic kin of Gaul and the Rhineland, and sharing their La Tène culture, the tribes of the southeast were developing rapidly. Their villages approximated true towns and their kings struck coins, proof of emerging royal power. The tribes of the north and west were isolated and poorer, still relying on hill forts for defense. Caesar, Julius Claudius I Agricola, Gnaeus Julius Hadrian





Caesar’s campaign against the Nervii in northern Gaul led him in 55 b.c.e. to make an expedition across the channel against their British allies. With a small force, he landed on the Kentish coast, but storm damage to his fleet and British resistance forced his withdrawal that fall. He was more successful the following year, as he defeated Cassivellaunus of the Catuvellauni near present-day St. Albans, took hostages, required payment of tribute, claimed to have conquered Britain, and left, never to return. Civil wars from 49 to 30 b.c.e. and then the organization of Gaul (which included modern France and parts of Germany and Italy) and the establishment of the Rhine frontier kept Rome out of Britain for almost a century. Diplomacy sought to maintain a rough equality among the tribes by supporting kings or factions and to prevent British assistance to revolts inside Roman Gaul. Finds of Roman coins and wine amphoras indicate a sporadic luxury trade. Anti-Roman Catuvellaunian expansion in Essex and across the south necessitated a change in Roman policies.

Claudius I decided to conquer Britain. He dispatched Aulus Plautius at the head of an army of four legions (fifty-five hundred men each) plus an equal number of auxiliary troops in 43 c.e. The force landed in Kent, crossed the Thames, and captured Camulodunum (Colchester), which had recently become the Catuvellaunian capital. Leaving Legio XX Valeria at Camulodunum, three army corps fanned out to overrun the lowlands. Legio II Augusta pacified the southern region under the command of Vespasian. Legio XIV Gemina—joined by Legio XX Valeria in 49 c.e.—thrust into the Midlands, and Legio IX Hispana marched through East Anglia.

By 47 c.e., the new province embraced lands south and east of the Humber and Severn Rivers. A military road, the Fosse Way, ran from Exeter (a base of Legio II) northeast to Lincoln (a base of Legio IX) and marked the limit of Roman control. The decommissioned fortress at Camulodunum became a colonia and the provincial capital; Verulamium (near St. Albans) and Londinium (London) were flourishing symbols of Roman rule. Two tribal kings surrendered in time to preserve independence as client rulers: Cogidubnus in Surrey-Hampshire and Prasutagus (d. 60 c.e.) in Norfolk.

Subsequent Roman advances were much more difficult because of highland terrain and stiffening resistance. The Silures in eastern Wales, the Ordovices in northern Wales, and the Brigantes in Yorkshire proved to be intractable. The harsh annexation of Prasutagus’s kingdom after his death sparked a revolt led by his widow Boudicca in c. 60 c.e. Her army sacked Camulodunum, Londinium, and Verulamium, but the disciplined army of the governor Suetonius Paulinus destroyed it.

Under the Flavian Dynasty (69-96 c.e.), Rome expanded the province and improved the quality of its rule. The laudatory biography of Gnaeus Julius Agricola by his son-in-law Tacitus (c. 56-c. 120 c.e.) has made that governor’s activities famous. His predecessors Cerealis and Frontinus (35-c. 103 c.e.) subjugated the Brigantes and the tribes of Wales, freeing Agricola to push against Caledonia (Scotland) and begin construction of a fortress for Legio XX at Inchtuthil on the Tay. It was abandoned unfinished as troubles on the Danube compelled the withdrawal from the Highlands and the reduction of the British garrison to three legions. Legion IX occupied Eburacum (York), while Legions II and XX moved to Isca (Caerleon) and Deva (Chester); all three proved to be permanent.

The cities destroyed by Boudicca were rebuilt, and Londinium, the hub of the road network and the possessor of an excellent harbor, soon became the capital. Archaeology has uncovered the governor’s palace, the forum, some streets, and wharves. Two former legionary fortresses became coloniae: Lindum colonia (Lincoln) and Glevum castra (Gloucester fort). To promote Romanization and easier provincial administration, the governors fostered Roman-style towns as civitas-capitals (canton-capitals), which controlled the surrounding countryside. Early examples are Canterbury and Chelmsford; more appeared under the Flavians—Chichester, Silchester, Winchester, Dorchester, Exeter, Cirencester, Caistor-by-Norwich, Leicester, and Wroxeter. Many of these places have continued to flourish as cities to modern times, so knowledge of them has increased through urban archaeology. Wroxeter and Silchester are uninhabited, and studies of them have provided the most complete information of Romano-British towns.

Caesar’s forces land in Britain.

(F. R. Niglutsch)

Literary sources necessary for narrative history practically cease at the recall of Agricola in 84 c.e. Legio IX was transferred out of Britain about 110 (the old view that it was destroyed in a rebellion around the year 117 is wrong). Hadrian came to Britain in 121, bringing a new governor (Platorius Nepos), a new legion (VI Victrix, which occupied York), and new ideas. The last civitas-capitals appeared in these years. Hadrian initiated the building of the famous wall, the best-known example among a number of linear barriers around the Roman Empire and stretching some 274 Roman miles (84 miles or 135 kilometers) from coast to coast from the mouth of the River Tyne to Solway Firth. Auxiliary troops (infantry and part-mounted cohorts) garrisoned forts at 5- or 6-mile (8- or 10-kilometer) intervals. Between each pair of forts were “milecastles” housing small contingents sent out from the forts, and watchtowers rose at 0.3-mile (0.5-kilometer) intervals, thus within sight of one another. Command headquarters and the largest single unit (a “milliary” cavalry wing, or ala) were at Stanwix near Carlisle. There were also several cavalry forts to the north of the wall, from which mounted patrols increased Roman surveillance.

Hadrian’s Wall, which marked the northern boundary of Britannia and the Roman Empire, stood guard against the tribes of the far north and prevented them from joining restless peoples within the province. The wall also allowed the Romans to collect customs. Although the wall made raids difficult, it was not intended to withstand large attacks. Invaders who overran it would have to contend with the legions moving up from York and Chester and reinforced auxiliary units closing in from behind.


The reign of Hadrian marks the end of the Roman conquest of Britain. In later years there were only occasional campaigns beyond the wall. The efforts of Antoninus Pius (86-161 c.e.) to hold a line between Edinburgh and Glasgow were soon abandoned. Septimius Severus (145-211 c.e.) fought up into the Highlands and died at York; his son Caracalla (188-217 c.e.) pulled back to the wall.

The parts of Britain that had adopted Roman customs and traditions, including agricultural practices, retained this way of life after the Romans departed. The Britons continued to inhabit many of the cities and use the roads that the Romans built. However, this mode of existence began a transformation during the late fourth century, when the Angles, Jutes, and Saxons started to invade Britain.

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Hill, Stephen, and Stanley Ireland. Roman Britain. London: Bristol Classical Press, 1996. Covers the Roman conquest of Britain from beginning to end. Bibliography.
  • citation-type="booksimple"

    xlink:type="simple">Jiménez, Ramón L. Caesar Against the Celts. New York: Sarpedon, 1996. An examination of Julius Caesar’s campaign against the Celts. Maps, bibliography, and index.
  • citation-type="booksimple"

    xlink:type="simple">Manley, John. A.D. 43: The Roman Invasion of Britain, a Reassessment. Stroud, Gloucestershire, England: Tempus, 2002. Archaeologist Manley examines the Roman invasion of Britain, casting doubt on some of the accepted beliefs in the light of archaeological discoveries.
  • citation-type="booksimple"

    xlink:type="simple">Peddie, John Conquest: The Roman Invasion of Britain. New York: St. Martin’s Press, 1997. Peddie describes the invasion of Britain in 43 c.e. by Roman forces. Bibliography and indexes.
  • citation-type="booksimple"

    xlink:type="simple">Salway, Peter. A History of Roman Britain. New York: Oxford University Press, 1993. Classical historian Salway examines the Romans’ view of Britain before the conquest, their conquest of Britain, and events during Britain’s existence as a Roman province. Bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Salway, Peter, ed. The Roman Era: The British Isles, 55 b.c.-a.d. 410. New York: Oxford University Press, 2002. Covers the Roman invasion of Britain and subsequent events. Bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Shotter, D. C. A. The Roman Frontier in Britain: Hadrian’s Wall, the Antonine Wall, and Roman Policy in the North. Preston, England: Carnegie, 1996. Shotter looks at how the Romans controlled Britain after the conquest, in particular, how they managed the northern border. Bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Todd, Malcolm. Roman Britain. 3d ed. Blackwell Classic Histories of England series. Malden, Mass.: Blackwell Publishers, 1999. A history of Roman Britain from the conquest to the end. Bibliography and index.
  • citation-type="booksimple"

    xlink:type="simple">Webster, Graham. The Roman Invasion of Britain. 1993. Reprint. New York: Routledge, 1999. A military history of the invasion of Britain by the Romans. Bibliography and index.
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Gnaeus Julius Agricola; Boudicca; Julius Caesar; Claudius I; Hadrian; Tacitus; Vercingetorix. Britain;Roman conquest of Roman Empire;conquest of Britain

Categories: History