Prior to the Roman conquest Britain was a country peopled by Celtic tribes, often at war with each other which left the country in a permanent state of unrest.

First Invasion of Roman Britain

Julius Caesar crossed the Channel in 55 and 54 BC which may have been a move intended to please his adoring public back home in Rome, although the Celts in Gaul had been receiving aid from their allies in southern Britain.

Julius Caesar left after two summers fighting exacting a promise of tribute from the defeated tribes and returned to Gaul. More about Julius Caesar’s Campaigns.

Second Invasion of Roman Britain

In 43 AD the Emperor Claudius in need of a boost to his domestic prestige ordered the invasion of Britain with four legions under the command of Aulus Plautius. The Romans landed at Richborough and pushed towards the River Medway, where they were met with stiff resistance. However, the young general Vespasian forced the river with his legion supported by a band of ‘Celtic’ auxiliaries, and the British were routed.

Meanwhile, Claudius arrived in Britain to enter the Catuvellaunian capital of Colchester in triumph. He founded a temple there, containing a fine bronze statue of himself, and established a legionary fortress. He remained in Britain for only 16 days.

The Romans quickly established control over the tribes of present day south eastern England. Further advance was slowed by a British chieftain of the Catuvallauni tribe, known as Caractacus who stirred up some resistance until his defeat and capture in 51.

Boudicca’s Revolt

In 60, while Governor Gaius Suetonius Paulinus was campaigning in Wales, a rebellion started in the SE of England, led by Queen Boudicca. Boudicca was widow of Prasutagus, king of the Iceni. Prasatugas had signed a peace treaty with the Romans, died. His wife, Boudicca intended to honour the treaty, but after the local Roman authorities seized Prasatugas’s property and raped his two daughters, Boudicca retaliated by signing a treaty with Trinovantes who were hostile to the Romans.

The revolt was suppressed, but not before the attacking and burning Verulamium (St Albans), Camulodunum (Colchester) and Londinium (London), leaving between seventy & eighty thousand people dead. The governor Agricola (AD 77–83) even also defeated the Scottish tribes at the Battle of Mons Graupius in AD 83, in the Grampian highlands.

Agricola Campaigns

By AD 70 Wales and the north had been subdued and under the command of Gnaeus Julius Agricola (AD 77–83) with Legions being located at York, Chester and Caerleon. Agricola moved northwards defeating the Caledonian tribes under the leadership of Calgacus at the battle of Mons Graupius in present day northeastern Scotland.

Building the Frontiers

The Romans gradually gave up their conquests in Scotland as troops were pulled back to deal with invasions on the Danube frontier, and the army gradually fell back to the Tyne–Solway frontier. It was here that the emperor Hadrian, visiting Britain in AD 122, ordered the building of his frontier wall. The emperor Antoninus Pius tried to reoccupy Scotland and built the short-lived Antonine Wall (AD 140–60). He was ultimately unsuccessful, however, and Hadrian’s Wall became the northern frontier of the province once more. Read about the frontier system of Roman Britain.

Invasion from the North

The Brigantes were still not subdued and shortly after AD 180 during the reign of Commodus there was an invasion by the northern tribes, who overran the wall. Commodus sent the general Ulpius Marcellus to quell the uprising. Around this time most of the cities of Britain were enclosed within earthen defensive walls, which may have been linked to the invasion.

The End of Roman Britain

During the 3rd and 4th centuries AD Britain was under threat of invasion by the Picts of Scotland, the Scots from Ireland, and the Saxons from Germany. 

Severus had divided Britain into two provinces, Britannia Inferior in the north (with its capital in York) and Britannia Superior in the south (with its capital in London). This division stopped too many troops from being concentrated in the hands of a single governor who may be tempted to become the new Emperor.

In the 4th century Britain Emperor Diocletian reorganised Britain as a ‘diocese’ consisting of four provinces, with military forces under the command of the Dux Britanniarum – the Duke of the Britains.

Britannia, distant from Rome, was often subjected to barbarian invasions or usurpations by imperial pretenders, and, in AD 410 Rome itself was sacked by the Visigoths and the Emperor Honorius declared that Britain would have to look after itself.