In AD 43, the Roman emperor Claudius ordered a major invasion of Britain. An army commanded by Aulus Plautius crossed the English Channel, defeated British resistance and established a permanent Roman presence on the island. The campaign strengthened Claudius’s political position and began a conquest that would transform much of Britain over the following decades.
Britain Before the Roman Conquest
Before the Roman invasion, Britain was inhabited by numerous communities with their own rulers, territories and identities. Ancient writers frequently described these peoples collectively as Britons, but they did not form a single united nation.
Political authority was often controlled by local kings and aristocratic families. Alliances, rivalries and warfare connected neighbouring communities, while the influence of individual rulers could expand or decline rapidly.
Most people lived in rural settlements and depended upon farming. They cultivated grain, raised livestock and produced metalwork, pottery, textiles and other goods.
Large hillforts existed in many regions, although not all served the same purpose. Some were defensive centres, while others acted as places of trade, production, ceremony or political gathering.
Southern Britain had extensive commercial links with continental Europe. Imported wine, pottery and luxury goods reached British elites, while grain, metal, livestock and enslaved people may have been exported.
Roman Knowledge of Britain
Romans knew of Britain long before the conquest. Mediterranean merchants and explorers had gathered information about the island and its resources.
Britain was associated with tin, which was essential for making bronze. Ancient geographical knowledge remained incomplete, but trade connected parts of the island with Gaul and the wider Roman world.
Roman leaders also understood that political events in Britain could affect Gaul. British rulers maintained relationships with communities across the Channel and could provide refuge or military support to Rome’s enemies.
Julius Caesar’s First Expedition
Julius Caesar led the first Roman military expedition to Britain in 55 BC during his conquest of Gaul. He claimed that British communities had assisted his Gallic opponents.
Caesar crossed the Channel with a relatively small force. His cavalry could not reach Britain at the same time, limiting his ability to conduct a major campaign.
British warriors attempted to prevent the Romans from landing. They used chariots and took advantage of their knowledge of the coastline.
The Roman soldiers struggled to leave their ships and form a battle line in deep water. Once they reached land, however, their discipline and equipment forced the defenders to withdraw.
Storms damaged Caesar’s fleet, and supply problems prevented an extended campaign. He accepted promises and hostages from some British leaders before returning to Gaul.
Caesar’s Second Expedition
Caesar returned in 54 BC with a much larger army. His forces advanced inland and crossed the River Thames despite British resistance.
The principal British leader opposing him was Cassivellaunus, who relied on mobility and chariot warfare rather than confronting the legions in a conventional battle.
Caesar attacked Cassivellaunus’s stronghold and gained support from rival British communities. Political divisions made coordinated resistance difficult.
Cassivellaunus eventually agreed to peace and promised tribute. Caesar then returned to Gaul without leaving a permanent occupation force.
His expeditions did not conquer Britain, but they increased Roman knowledge of the island and allowed later emperors to claim that Britain already lay within Rome’s sphere of authority.
Rome and Britain After Caesar
During the following century, relations between Rome and southern Britain developed through diplomacy, trade and political alliances. British rulers imported Roman goods and sometimes placed Latin inscriptions on their coins.
Some kings were recognised as friends and allies of Rome. These relationships allowed Roman influence to grow without the expense of military occupation.
Augustus considered invading Britain but never launched a major campaign. Other concerns and diplomatic agreements made conquest unnecessary during his reign.
The emperor Caligula also planned an expedition. Ancient writers mocked his preparations and claimed that he ordered soldiers to collect seashells as spoils from the ocean.
The exact events are uncertain. Caligula may have abandoned a genuine campaign because of logistical problems, military unrest or changing political circumstances.
Claudius Becomes Emperor
Claudius became emperor in AD 41 after the assassination of Caligula. He had little military experience and had not been the expected successor.
His position depended heavily upon the Praetorian Guard, whose soldiers had proclaimed him emperor. A successful foreign conquest could strengthen his authority and give him the military prestige expected of a Roman ruler.
Britain offered an attractive target. It was close to the existing provinces, possessed valuable resources and could be presented as a land beyond the limits reached by earlier Roman commanders.
The Political Cause of the Invasion
The immediate justification for intervention involved Verica, a British ruler associated with the Atrebates in southern Britain. He had maintained friendly relations with Rome but was driven from his territory.
Verica fled to the Roman Empire and appealed to Claudius for assistance. Rome could therefore present the invasion as the restoration of an allied king.
Verica’s enemies were probably connected with the Catuvellauni, a powerful kingdom centred north of the River Thames. Under leaders such as Cunobelinus, the Catuvellauni had expanded their influence across southeastern Britain.
After the death of Cunobelinus, his sons Caratacus and Togodumnus emerged as leading opponents of Rome. Their growing power threatened rulers who depended upon Roman support.
Preparing the Invasion
Claudius entrusted command of the invasion to Aulus Plautius, an experienced senator and military commander. Plautius received a force of four legions supported by auxiliary units.
The legions traditionally associated with the invasion were the Second Augusta, the Ninth Hispana, the Fourteenth Gemina and the Twentieth Valeria Victrix. The precise form of some legionary titles may have changed over time.
The auxiliary troops included cavalry, archers and specialised infantry recruited from different parts of the empire. They provided skills that complemented the heavily armed legionaries.
The complete invasion force may have numbered around forty thousand soldiers, although the exact total is unknown. Thousands of sailors, labourers, merchants and other civilians also supported the operation.
The Soldiers Refuse to Sail
Ancient accounts state that the soldiers initially refused to embark. Britain lay beyond the familiar boundaries of the Roman world and was surrounded by a dangerous ocean.
The imperial freedman Narcissus was sent to address the troops. Soldiers reportedly mocked him by shouting a traditional command associated with freed people during a festival.
The strange confrontation broke the tension, and the army eventually agreed to sail. The story may have been shaped for dramatic effect, but it suggests that the expedition caused genuine anxiety.
Crossing the Channel
The invasion fleet crossed the English Channel in AD 43. The exact departure point and landing place remain debated.
Richborough in Kent has traditionally been identified as the principal landing site because it later became an important Roman military and transport centre. Other interpretations suggest landings farther west, possibly near Chichester.
The Romans may have used several routes and landing points to confuse the defenders and move a large force efficiently. Archaeological evidence continues to shape debate about the invasion’s opening phase.
The Britons did not immediately oppose the landing in a major battle. They may have expected the Romans to withdraw as Caesar had done, or they may have moved inland to choose more favourable ground.
The Search for the British Army
Aulus Plautius advanced into southeastern Britain. The defenders avoided immediate confrontation and attempted to use rivers, forests and marshes to delay the Roman army.
Roman forces depended upon organised supply lines. Moving tens of thousands of soldiers required food, equipment, animals and secure communications with the coast.
The legions constructed marching camps and used engineers to overcome natural obstacles. Their discipline allowed them to maintain an advance through unfamiliar territory.
The Battle of the Medway
The first major battle probably occurred near the River Medway in Kent. The British army used the river as a defensive barrier and may have expected the Romans to struggle with the crossing.
Auxiliary soldiers from the Batavians were trained to swim across rivers while carrying their equipment. They crossed unexpectedly and attacked British chariot horses, disrupting the defenders’ mobility.
Roman forces then fought to establish a secure crossing. The engagement reportedly continued for two days, suggesting that British resistance was determined.
On the second day, a Roman force commanded by Titus Flavius Vespasian attacked the defenders from an unexpected direction. Vespasian later became emperor, but at this time he commanded the Second Legion.
The British army was eventually forced to retreat. The victory opened the route towards the Thames and the political centre of the Catuvellaunian kingdom.
The Crossing of the Thames
The Britons withdrew beyond the River Thames and attempted to use difficult marshland against their pursuers. Local knowledge allowed them to move through areas dangerous to outsiders.
Roman troops followed, but some became trapped or suffered losses in the marshes. The Batavian auxiliaries again helped cross the river.
The Romans eventually forced another passage and continued their advance. Togodumnus was killed during this phase of the campaign or died soon afterwards.
His death did not immediately end resistance. British forces remained active, and Plautius paused to await the arrival of Emperor Claudius.
Claudius Arrives in Britain
Claudius travelled from Rome to join the invasion. His visit was brief, perhaps lasting only sixteen days in Britain.
He brought additional troops, senior officials and possibly war elephants. The appearance of elephants would have created a powerful psychological effect among defenders unfamiliar with the animals.
Claudius took formal command during the capture of Camulodunum, the modern city of Colchester. It had been an important centre of Catuvellaunian power.
Several British rulers submitted to the emperor. Their surrender allowed Claudius to present the campaign as a decisive conquest, even though Roman control remained limited mainly to the southeast.
Claudius Celebrates Victory
Claudius returned to Rome and celebrated a triumph in AD 44. He received the honorary title Britannicus, although he later gave the name to his son.
Coins and monuments advertised the conquest throughout the empire. Images showed Claudius receiving the submission of Britain or standing above a defeated female figure representing the island.
The victory strengthened his position as emperor. A ruler once criticised for lacking military experience could now claim to have conquered territory beyond the achievements of Julius Caesar.
The triumph exaggerated the completeness of the victory. The invasion had established a permanent foothold, but decades of warfare would be required to extend Roman power across much of the island.
Vespasian’s Campaigns
While Claudius returned to Rome, his commanders continued the conquest. Vespasian led the Second Legion through southern and southwestern Britain.
Ancient sources credited him with fighting numerous battles, capturing more than twenty settlements and subduing the Isle of Wight.
His campaigns probably extended Roman control through parts of modern Hampshire, Dorset and neighbouring regions. The capture of fortified sites demonstrated the ability of Roman troops to overcome organised local resistance.
Vespasian’s achievements contributed to the military reputation that later helped him become emperor in AD 69.
The Roman Alliance With Cogidubnus
Rome did not rely entirely upon direct military rule. Friendly British rulers helped stabilise conquered territory and extend Roman influence.
One important ally was Cogidubnus, whose name also appears in slightly different forms. He governed territory in southern Britain and remained loyal to Rome.
His centre may have been connected with the palace complex at Fishbourne near Chichester. The luxurious site demonstrates how local elites could adopt Roman architecture and material culture.
Client rulers reduced the number of troops Rome needed to control the region. Their territories could later be incorporated more directly into the province.
The Roman Colony at Camulodunum
Camulodunum became an important centre of Roman power. Veterans were settled there in a colony, receiving land in conquered territory.
The colony demonstrated that Rome intended to remain permanently. It also rewarded soldiers and created a loyal population in a strategically important area.
A large temple dedicated to the deified Claudius became a visible symbol of imperial authority. Many Britons, however, resented the loss of land and the behaviour of some veterans.
These tensions later contributed to the destruction of Camulodunum during the revolt led by Boudica.
The Creation of the Province
Conquered territory was organised as the Roman province of Britannia. A governor commanded the army and supervised administration on behalf of the emperor.
The governor possessed significant authority because Britain remained an active military zone. Legionary commanders, auxiliary officers and financial officials supported provincial government.
Rome introduced taxation, censuses and legal structures. Existing communities were reorganised into administrative districts often based around regional towns.
Local aristocrats could retain influence by cooperating with the new government. Roman rule depended upon their assistance in collecting taxes, administering justice and maintaining order.
Roads and Forts
The army constructed a network of roads linking the invasion bases with forts and developing towns. These roads allowed soldiers, supplies and official messages to move rapidly.
Watling Street connected the southeast with the Midlands and later with western military zones. Other routes developed towards the southwest, north and east.
Forts were established at strategic crossings, supply centres and frontier locations. Some temporary military settlements later developed into permanent towns.
The road network served both conquest and administration. It also encouraged trade and movement between communities.
Caratacus Continues the Resistance
Caratacus escaped from southeastern Britain and continued resisting Rome in the west. He gained support among peoples traditionally identified as the Silures and Ordovices.
For several years, he used difficult terrain and mobile warfare to challenge Roman forces. His resistance demonstrated that the capture of Camulodunum had not ended organised opposition.
In AD 50 or 51, the governor Publius Ostorius Scapula confronted Caratacus in a major battle. The Britons selected a defensive position protected by steep ground, a river and stone barriers.
Roman discipline and equipment eventually overcame the defences. Caratacus’s family was captured, but he escaped and sought protection from Cartimandua, queen of the Brigantes.
Cartimandua was a Roman ally and handed Caratacus over to the authorities. He was taken to Rome and displayed before Claudius.
Caratacus Before Claudius
According to the historian Tacitus, Caratacus delivered a dignified speech before the emperor. He argued that his resistance had increased the glory of Rome’s victory and asked to be spared.
Claudius granted mercy to Caratacus and his family. The decision allowed the emperor to display confidence and generosity towards a defeated enemy.
The exact words of the speech were probably shaped by Tacitus, but the episode became one of the most famous stories associated with the conquest.
Resistance Among the Silures
The capture of Caratacus did not end resistance in western Britain. The Silures continued fighting Roman forces in what is now South Wales.
Their knowledge of the terrain allowed them to conduct ambushes and avoid decisive defeat. Roman commanders faced a prolonged and costly struggle.
Permanent conquest required forts, roads and repeated campaigns. Roman control spread unevenly rather than through one continuous advance.
The Druids and Anglesey
Roman writers associated druids with religion, law, education and political influence among some British and Gallic communities. They portrayed the island of Mona, modern Anglesey, as an important centre of druidic activity.
In AD 60 or 61, the governor Gaius Suetonius Paulinus attacked the island. Roman accounts described defenders gathering along the shore while druids and women called upon the gods.
The Roman soldiers initially hesitated but then crossed and defeated the opposition. Sacred groves were destroyed, and the Romans attempted to suppress practices they considered threatening or unacceptable.
While Suetonius was occupied in Wales, a much larger crisis erupted in southeastern Britain.
The Revolt of Boudica
Boudica was queen of the Iceni, a people living in eastern Britain. Her husband Prasutagus had ruled as a Roman ally.
After his death, Roman officials attempted to absorb his kingdom. According to Tacitus, Boudica was beaten and her daughters were assaulted.
The Iceni rebelled and were joined by the Trinovantes and other dissatisfied communities. Their forces destroyed Camulodunum before attacking Londinium and Verulamium.
The rebels killed inhabitants and burned Roman settlements. Archaeological evidence preserves layers of destruction associated with the revolt.
Suetonius returned from Wales and assembled a smaller but disciplined army. He selected a narrow battlefield that prevented the Britons from surrounding his forces.
The Roman army defeated Boudica’s much larger force. The revolt collapsed, and Boudica died soon afterwards, either from illness or by taking poison.
Changes After the Revolt
The Boudican revolt exposed serious failures in Roman provincial government. Aggressive taxation, confiscation and mistreatment by officials had helped create widespread anger.
After suppressing the uprising, Roman authorities adopted a more cautious approach. The new administration attempted to combine military security with less confrontational government.
Reconstruction followed the destruction. Londinium recovered and developed into the province’s principal commercial and administrative centre.
The Conquest of Northern Britain
Roman armies continued moving north during the later first century AD. Governors built forts and roads while confronting communities across Wales and northern England.
Under the Flavian emperors, the general Gnaeus Julius Agricola conducted extensive campaigns. Tacitus, his son-in-law, later wrote an account of his life and achievements.
Agricola advanced into Scotland and defeated a northern army at the Battle of Mons Graupius, traditionally dated to AD 83 or 84. The exact location of the battle remains unknown.
Roman forces reached far into northern Britain, but they did not permanently occupy every conquered area. Troops were withdrawn for campaigns elsewhere, and control contracted towards more defensible frontiers.
Hadrian’s Wall
When Emperor Hadrian visited Britain in AD 122, he ordered the construction of a fortified frontier across northern England.
Hadrian’s Wall extended from the River Tyne to the Solway Firth. It included stone and turf barriers, forts, milecastles, towers, roads and defensive ditches.
The wall did not create an entirely sealed border. Gates allowed movement, trade and military patrols while helping Rome supervise people crossing the frontier.
It represented a change from expansion towards controlled defence. The empire would no longer attempt to conquer the whole island permanently.
The Antonine Wall
During the reign of Antoninus Pius, Roman forces advanced north again. They constructed a new frontier across central Scotland around AD 142.
The Antonine Wall was built mainly from turf and timber and stretched between the Firth of Forth and the Firth of Clyde.
Rome occupied the line for only a limited period. By the later second century, the army had largely returned to Hadrian’s Wall.
The repeated movement between these frontiers demonstrates the difficulty of maintaining permanent control in northern Britain.
The Roman Army in Britain
Britain remained one of the most heavily militarised provinces of the empire. Several legions and numerous auxiliary units were stationed there.
Soldiers came from many regions, including Gaul, Spain, Germany, the Balkans, North Africa and the eastern provinces. Their movement made Roman Britain culturally diverse.
Military bases attracted traders, craftspeople and soldiers’ families. Civilian settlements developed outside forts and became centres of local economic activity.
The army consumed large quantities of grain, animals, leather, pottery and metal goods. Supplying the frontier connected rural communities with imperial markets.
Towns and Urban Life
Roman rule encouraged the growth of towns as centres of administration, trade and public life. Londinium, Camulodunum and Verulamium became especially important.
Towns contained streets, markets, temples, bathhouses and public buildings. Wealthy residents financed construction to display civic pride and loyalty to Rome.
Some settlements followed planned street layouts, while others grew gradually around military or commercial centres.
Urban life was never experienced equally across Britain. Many people continued living in farms and villages with limited direct contact with major towns.
Baths and Public Buildings
Bathhouses were important social institutions in Roman towns and military settlements. They provided spaces for washing, exercise, conversation and business.
Public buildings expressed Roman ideas about citizenship and civic identity. Basilicas provided space for administration and legal activity, while temples connected local religion with imperial power.
The complex at Bath developed around natural hot springs sacred to the local goddess Sulis. The Romans identified her with Minerva, creating the combined deity Sulis Minerva.
This blending of traditions illustrates how Roman and local religious practices could interact rather than simply replacing one another.
Villas and the Countryside
In parts of southern and eastern Britain, wealthy landowners constructed villas combining residential comfort with agricultural production.
Some villas contained mosaics, painted walls, bath suites and heated rooms. Their architecture displayed the owner’s wealth and participation in Roman provincial culture.
Most rural inhabitants lived more modestly. Traditional roundhouses and local settlement patterns continued in many regions long after the conquest.
The countryside produced food and raw materials for towns, forts and the army. Roman taxation and market demand altered patterns of production.
Trade and Natural Resources
Roman Britain exported agricultural goods and natural resources. Mining expanded in regions containing lead, silver, copper, iron and gold.
Imported pottery, wine, olive oil and luxury goods arrived from continental Europe and the Mediterranean. Amphorae and coins provide evidence for extensive trade networks.
Roads and ports improved communication, but transport remained expensive and difficult. Rivers and coastal shipping continued to be essential.
Economic change varied between regions. Communities near towns, military bases and major roads often experienced the strongest effects.
Language and Literacy
Latin became the language of government, the army, law and many inscriptions. Members of local elites used Latin to participate in Roman administration.
Writing became more widespread, although literacy remained limited. Inscriptions appeared on monuments, tombstones, pottery and everyday objects.
The writing tablets discovered at Vindolanda near Hadrian’s Wall preserve letters, lists and military records. They offer rare evidence for the daily lives of soldiers and their families.
Local languages continued to be spoken. Roman Britain was linguistically diverse, and Latin did not completely replace earlier forms of speech.
Religion in Roman Britain
Roman Britain contained a wide range of religious practices. Traditional local deities continued to be worshipped alongside gods introduced from Rome and other provinces.
Worshippers often combined Roman and British divine names. This allowed local sacred traditions to exist within a wider imperial religious system.
Soldiers and merchants introduced cults from distant regions. Mithras, Isis, Jupiter, Mars and many other deities received worship in different communities.
The imperial cult honoured the emperor and Rome. Participation could express political loyalty as well as religious devotion.
Christianity also reached Britain during the Roman period, although its early development is difficult to reconstruct. By the fourth century, British bishops were participating in church councils.
Romanisation and Cultural Change
The term Romanisation was once used to describe a simple process in which conquered peoples adopted Roman culture. Modern historians often prefer a more complex interpretation.
People adopted Roman objects, language and customs for many different reasons. These choices could provide status, economic advantage or access to political power.
Local identities did not disappear. Communities combined imported practices with existing traditions to create distinct forms of provincial life.
Roman culture itself was not uniform. Soldiers, officials, merchants and settlers brought influences from every part of the empire.
Resistance and Cooperation
The history of Roman Britain included both resistance and cooperation. Some communities fought the invaders, while others formed alliances or adapted to the new government.
These responses could change over time. A ruler might support Rome against a local rival, while descendants could later rebel against Roman demands.
Cooperation did not necessarily mean complete acceptance of conquest. It could be a practical strategy for preserving land, status or community influence.
Rome’s success depended as much upon alliances and local administration as upon battlefield victories.
The Limits of the Conquest
Rome never completed the conquest of the entire island. Much of modern Scotland remained beyond lasting imperial control, while Ireland was never incorporated into the empire.
The landscape, distance and resistance of northern communities made permanent occupation expensive. Rome had to balance ambitions in Britain against military needs elsewhere.
Even within the province, Roman influence varied. The southeast became highly urbanised, while many western and northern regions remained dominated by military settlements and rural communities.
The invasion of AD 43 therefore began a long and uneven process rather than producing an immediate conquest.
The End of Roman Rule
During the fourth century, Britain faced political instability, economic change and attacks from outside the province. Troops were sometimes withdrawn to support rival emperors or defend other frontiers.
In the early fifth century, the Western Roman government could no longer provide effective military protection. Imperial administration in Britain ended around AD 410.
Roman towns, villas and institutions did not all disappear at once. Communities adapted in different ways, and elements of Roman culture survived beyond the end of official rule.
The Legacy of the Invasion
The invasion of AD 43 permanently changed Britain’s relationship with Europe and the Mediterranean. Roads, towns, forts and ports connected the island to an empire extending across three continents.
Roman government introduced new administrative systems, forms of taxation and legal practices. Latin writing, imported goods and imperial religious traditions became part of provincial life.
The conquest also brought warfare, enslavement, land confiscation and the violent suppression of resistance. Its effects were unequal and depended upon region, wealth and political status.
Claudius’s invasion succeeded because Rome combined disciplined military force with diplomacy and cooperation from British allies. The initial victories established a foothold, but generations of soldiers and governors were required to extend and defend the province.
The Roman invasion was therefore not a single event completed in AD 43. It was the beginning of a long struggle over power, identity and territory that shaped Britain for almost four centuries.