Roman conquest of Britain


The Roman conquest of Britain was a military and political effort to project Roman power into the northeast Atlantic, a gradual process that began in AD 43, under Emperor Claudius (AD 10-AD 54) and was largely completed in the 87, when the Stanegate, or 'stone road', was established as the northern border.

In the years after Claudius arrived, as many as half a dozen of the major British tribes submitted to Rome.

The Roman army was generally recruited from Italy, Hispania, and Gaul. To cross the English Channel they used the newly formed Classis Britannica fleet equipped with Mediterranean war galleys, which were much thicker in wood and more stable in rough waters.

The Romans under their general Aulus Plautius (c. 5 BC-AD 57) first made their way inland in various battles against British tribes, including the Battle of the Medway (43 AD), the Battle of the Medway River (43 AD), and , in later years, the Battle of Caer Caradoc (50 AD) against Caratacus (15 AD-54 AD) and the Battle of Mona (60/61 AD) on Anglesey.

After a widespread uprising in AD 60 in which the British under Boudicca (26-61) plundered Camulodunum, Verulamium and Londinium, the Romans crushed the rebellion at the Battle of Watling Street (AD 60-61) and continued their offensive towards north to the center of Caledonia at the Battle of Mount Graupius (83-84 AD). Even after Hadrian's Wall was established as a frontier, the tribes of Scotland and northern England repeatedly rebelled against Roman rule and continued to hold forts in northern Britain to ward off these attacks.

The war continued for generations, but the conquest of Britain, which began in AD 43, was aimed at consolidating Emperor Claudius in power and proving his worth, who then appeared on the island and visited the city of Camulodunum.


The island had always aroused great interest in Rome due to its natural wealth. At the same time, the Atlantic route from the Mediterranean began to be used intensively for the transport of food destined for the legions based on the Rhenish border of Africa and Hispania. But especially Britain had become a haven for the Gallic rebels, so it was urgent to subdue it.

The circumstances seemed to favor a possible conquest since the territory was immersed in different succession struggles. On the one hand, the leader of the Cunobelino tribe (3-41 AD) had died leaving his lands to his two sons. Further south, the neighboring kingdom was also mired in internal strife that had caused its king to flee to Roman lands in search of asylum.

Across the channel in Bononia, a future raid had been planned for a long time since Caligula (12 AD-41 AD) had already recruited two legions on his expedition north to facilitate a future invasion of Britain without reducing the forces of Germania.

When Emperor Claudius (10 BC-AD 54) embarked on one of the most ambitious projects of his reign, for him the exploration of new lands beyond the northern ocean had a special meaning as his father, Drusus the elder (39 BC-9 BC), had been one of the first to navigate its waters in 12 BC. Years later it would be his brother Germanico (15 BC-19 AD) who dedicated himself to exploring these unknown waters. However, the soldiers were not very interested in embarking on an adventure through mysterious lands, as rumors about them said that witchcraft practices were common there and that they were inhabited by ferocious savages who practiced human sacrifice.

Claudius longed to follow in the footsteps of his father and brother, to whom he professed great admiration and affection, but he was not going to settle for simple explorations but wanted to give the Roman people a new province, retaking the conquest that Caesar (63 BC-14 AD) had left incomplete: Britannia.

Britain was known during classical antiquity as a great source of tin. The island had probably been explored by the Greek geographer Pytheas (350 BC-285 BC) in the 4th century BC, and by the Carthaginian navigator Himilcon (around 450 BC) in the 5th century BC, but its position separated by the ocean from the rest of the known world, gave it a high degree of mystery. Some historians even insisted that its existence was a lie, and Pytheas's journey was dismissed as a fallacy.

By the year 40 d. C., the political situation in Britain was very unstable. The Catuvellaunos had displaced the Trinovantes as the most powerful kingdom in southeastern Britannia, taking the ancient Trinovantian capital of Camuloduno, and initiated a policy of pressure towards their neighbors Atrébates, led by the descendants of Julius Caesar's former ally and later enemy, Comio (? -20 BC).

During the period in which Caesar was appointed proconsular governor of the Gallic provinces and went to war against practically all the peoples of the region, initiating a conflict that would go down in history with the name of the Gallic War (58 BC-51 BC) Britain was living its Iron Age in its secluded corner of the world. Ancient sources estimate that, at this time, the island would have approximately one million inhabitants.

When the general of the Roman republic Julius Caesar and his army first reached the south of the island of Great Britain, known as Britain to the Romans, they were reaching the limit of the known world. It was the beginning of a conquest, which would be consummated 150 years later. But it was also the first step for Britannia to join the Roman world, which consequently brought science, astronomy, architecture, writing, and a more complex social structure.

Britain later became part of an empire that stretched from the Caspian and the Persian Gulf to the Iberian Peninsula; and from North Africa to the Scottish Borders to become part of the known world.

The Invasions of Julius Caesar

In the course of his Gallic wars, Julius Caesar invaded Britain twice: 55 and 54 BC. On the first occasion, Caesar brought with him only two legions and 80 ships in the summer to cross the English Channel and reach Britain. However, due to the storms he managed little more than a landing on the Kent coast.

This is how the general himself narrated this fact in his historiographical work "Bellum Gallicum":

'Because of the storms, the reinforcement fleet had to withdraw to the Gallic shores. Many ships were destroyed, leaving the rest useless for navigation, without cables, without anchors, without a trace of rigging, it was, as was very regular, an extraordinary disturbance in the entire army, since they did not have other ships for re-embarkation, nor any preparations to repair the others. '

The second invasion took place in AD 54. when he reassembled his legions and returned to Britain. In this case better equipped and with many more provisions and men, he was more successful, although Caesar failed to conquer territory for the republic. This invasion consisted of 628 ships, five legions, and 2,000 horsemen.

The force was so imposing that the British did not dare to contest Caesar's landing in Kent, but waited until he began to move inland.

Caesar eventually penetrated Middlesex and crossed the Thames, forcing the British warlord Cassivellaunus to surrender as a tributary of Rome and establishing Mandubracius of the Trinovantes as client king. At that time it was the beginning of the submission and romanization of the most prominent tribes of the Druid lands.

First Invasion - 55 BC

Caesar claimed that, in the course of his conquest of Gaul, the Britons had supported the campaigns of the continental Gauls against him, with fugitives from among the Belgian Gauls fleeing to the Belgian settlements in Britain, and the Venice of Armorica, who controlled maritime trade to the island, asking for help from his British allies to fight for them against Caesar in 56 BC.

Strabo (63 BC-AD 23) says that the Venetian rebellion of 56 BC was intended to prevent Caesar from traveling to Britannia and disrupting his commercial activity, suggesting that by then the possibility of a British expedition had been considered.

At the end of the summer of 55 a. C., although it was late in the campaign season, Caesar decided to make an expedition to Britannia. He called in the merchants who traded with the island, but they were unable or unwilling to provide useful information about the inhabitants and their military tactics, or which ports he could use, presumably not wanting to lose his monopoly on inter-channel trade. He sent a tribune, Gaius Volusenus (mid-1st century BC), to explore the coast in a single warship. He probably surveyed the Kentish coast between Hythe and Sandwich, but was unable to disembark, as "he did not dare to leave his ship and entrust himself to the barbarians", and after five days he returned to give Caesar the information he had managed to gather.

By then ambassadors had arrived from some of the British states, warned by merchants of the impending invasion, promising their submission. Caesar sent them back, along with his ally Commius, king of the Belgae Atrebates, to use their influence to conquer as many other states as possible.

He assembled a fleet composed of eighty transport ships, enough to transport two legions, and an unknown number of warships under a quaestor, in an unnamed port in Morini's territory, almost certainly Portus Itius (Boulogne). Another eighteen cavalry transports were to set sail from a different port, probably Ambleteuse. Clearly in a hurry, Caesar himself left a garrison in port and departed "in the third watch," long after midnight on 23 August with the legions, leaving the cavalry to march on to their ships, embark, and meet with him as soon as possible.

In light of later events, this was either a tactical error or (coupled with the fact that the legions arrived without baggage or heavy siege equipment) confirms that the invasion was not intended for total conquest.


The Britons again sent ambassadors and Caesar, although he doubled the number of hostages, realized that he could not take it any longer and did not dare to risk a stormy crossing in winter. 

Caesar had left at the end of the campaign season and winter was approaching, so he allowed them to be taken to Gaul, where he returned with all the ships that could be repaired with the remains of the sunken ships. Even then, only two tribes felt threatened enough by Caesar to send the hostages, and two of his transports broke away from the main body and made landfall elsewhere. 

If the invasion was intended to be a full-scale campaign, invasion or occupation, it had failed, and if it's seen as a continuous reconnaissance or show of force to deter further British aid to the Gauls, it was not enough. It's also suggested that this invasion established alliances with British kings in the area that softened the subsequent invasion of AD 43.

Caesar's pretext for the invasion was that "in almost every war with the Gauls relief had been provided to our enemy of that country." This is plausible, although it may also have been a cover for investigating the island's mineral resources and economic potential: then Cicero (106 BC-43 BC) refers to the disappointing discovery that there was no gold or silver on the island; and Suetonius (c.70-c.126 AD) reports that Caesar is said to have gone to Britain in search of pearls.

Second Invasion - 54 BC

A second invasion was planned in the winter of 55-54 for the summer of 54 BC. Cicero wrote letters to his friend Gaius Trebacius Testa (84 BC-AD 4) and his brother Quintus, both serving in Caesar's army, expressing his excitement at the prospect. He urged Trebacio to capture him in a war chariot and asked Quintus to write him a description of the island. Trebacio, as it turned out, did not go to Britain, but Quintus did, and from there he wrote several letters, as did Caesar himself.

Determined not to make the same mistakes as the previous year, Caesar mustered a greater force than on his previous expedition with five legions instead of two, plus two thousand horsemen, transported in ships that he designed, with experience in shipbuilding technology from Venetic, to be more suitable for a beach landing than those used in 55 BC, being wider and lower to facilitate grounding.

Titus Labienus (c.100-45 AD) stayed in Portus Itius to supervise the regular transports of food from there to the British beachhead. The military ships were joined by a flotilla of trading ships captained by Romans and provincials from across the empire and local Gauls, hoping to seize commercial opportunities. It seems more likely that the figure Caesar cites for the fleet (800 ships) includes these merchants and troop carriers, rather than just troop carriers.

Cesar landed at the spot he had identified as the best landing spot the year before. The Britons did not oppose the landing, apparently, as Caesar claims, intimidated by the size of the fleet, but this may have been a strategic ploy to give them time to rally their forces.

Upon landing, Caesar left Quintus Atrius in charge of the beachhead and made an immediate night march 12 miles inland, where he encountered British forces at a river crossing, probably somewhere on the River Stour. The Britons attacked but were driven back and attempted to regroup at a fortified place in the forest, possibly the hill fort at Bigbury Wood, Kent, but were again defeated and scattered.

As it was late and Caesar was not sure of the territory, he called off the chase and camped. However, the next morning, while preparing to move on, Caesar received word from Atrio that, once again, his anchored ships had crashed into each other in a storm and suffered considerable damage. About forty, he says, were lost.

The Romans were not used to the tides and storms of the Atlantic and the English Channel, but nevertheless, considering the damage it had suffered in the previous year, this was poor planning on Caesar's part. However, Caesar may have exaggerated the number of sunken ships to magnify his own accomplishment in saving the situation. He returned to shore, remembering the legions that had advanced, and immediately set out to repair his fleet. His men worked day and night for about ten days, stranding and repairing the ships and building a fortified camp around them.


Caesar did not conquer any region of Britain. However, the enthronement of Mandubracio meant the establishment of client kings on the island. In this way, Britannia remained within the area of ​​influence of Rome and, for more than a century, diplomatic and commercial relations were maintained. The British territory was left open for a possible conquest, which was finally carried out by Claudius in the year 43.

In the words of the Roman historian Cornelius Tacitus (c.55-c.120):

'The deified Julius Caesar was the first Roman to enter Britain at the head of an army: he established relations with the natives after defeating them in battle and became the owner of the coast and it can be considered that he indicated it to us but did not give it to us.'

De vita et moribus Iulii Agricolae, Cornelius Tacitus. XIII.  

Invasion, Conquest & Rebellions

Between the years 55 BC and 40 AD, the policy of paying tributes, exchange of hostages and vassalage of the British tribes, which began with the Roman invasions of Britain commanded by Julius Caesar during the Gallic War, remained largely unchanged. Caesar Augustus prepared the invasion of the island on three occasions (34 BC, 27 BC and 25 BC).

The first and third were aborted by unrest in other regions of the empire, and the second because British leaders seemed willing to come to terms to avoid war. Some historians suggest that the invading force sailed from Boulogne to Solent, landing in the vicinity of Noviomagus or Southampton, in territory officially ruled by Verica (early 1st century AD).

The resistance of the British was led by the leaders Togodumno (43 AD) and Caratacus (15-54 AD), sons of the King of the Catuvellaunos, Cunobelino (end of the 1st century BC - 40 AD). A major British force engaged the Roman invaders near Rochester on the River Medway. The battle went on for two days. The Roman general Hosidius Geta (20-95 AD) was captured during the fighting, but he was rescued and threw the fight off balance in favor of the Romans, being rewarded with a triumph when he returned to Rome. The British fell back towards the River Thames with the Roman army chasing them along the river and causing heavy casualties as they passed through Essex territory.

Boudica, the Celtic queen who challenged Rome

Boudica (30-61) was a heroine who led a gigantic army against the Roman legions to free Britain from its invaders.

It seems that his first target was perpetrated against the same legionaries who had razed his village and taken his family's wealth. However, Boudica was also a bloodthirsty queen who razed Rome's three major settlements on the islands and wiped out more than 80,000 civilians (many of them, after being tortured and burned alive) before being detained by the army of Gaius Suetonius Paulino (10-c.41). Still, and for many of her compatriots, this woman is considered the one who tried to free her people from the Roman Empire.

Following the defeat of the British insurgents under Queen Boudica, the subsequent governors sent by Rome to rule the province continued their conquest by advancing north to conquer Wales in AD 70.

Roman History in Great Britain

Today, almost two thousand years after the events, it's impossible to travel through Great Britain and not notice the passage of the Romans through those lands. Despite the centuries that have passed, its footprints are palpable everywhere. Cities like London, Chester, Manchester, Bath or York show us the ruins, walls, bridges, the creation of cities or roads left by the Romans.

During the 350 years of Roman occupation, Great Britain was a colony, and after the defeat of the country's rebellious tribes, the Romans remained the occupying power. It's legacy is made up of military and civil constructions: fortresses, walls and villages. It's long roads, laid out to facilitate the movement of troops, continue to cross the landscape.