In 5,600 BC the Black Sea in southern Russia flooded and caused major migrations of Europeans in all directions.
One of these migrations was of a group called the Celts, who settled Western Europe, including Britain and Ireland.
By 600 BC, a group of Celts called the ‘Britanni’ had invaded and settled in the British Isles, giving their name to the country.
Although the Celts did make a small addition to the British population, it was not as overwhelming as previously thought, making up only a small fraction of the present day British gene pool.
Nevertheless the Celtic way of life (culture) did become firmly established within the British Isles.
The Celts made such an important contribution to our island story that they are mistakenly referred to as the original British.
After arriving in Britain, the Britanni Celts established a huge number of hill top forts throughout the country.
It is unknown whether these hill top forts were created by the Celts for defence, or by the native British who tried unsuccessfully to defend themselves against the encroaching Celts.
Celtic art was magnificent, revolving around swirls and intricate designs.
It was the Celts who were responsible for bringing Iron working to Britain.
The Celts organised themselves into Clans, which was basically a small tribe.
The Celts lived in huts made of timber, and grouped together into hamlets.
Often Clans had their own coinage.
When they werenâ€™t fighting each other, the Celts took to farming, inventing the iron plough, which forced them to create long narrow fields which are still abundant in Britain today.
Life for Celtic women was better than in most societies of that time, and they could own property, choose their own husbands and were equal to men under the law.
A curious feature of the Celts was their priests, known as Druids.
They acted as holy men, political advisors, teachers, ambassadors, law enforcers and healers.
Some sources describe the Druids as the glue holding together Celtic culture.
The Celts loved war and were very aggressive.
They would paint themselves blue from head to foot and charge at their enemies screaming at the top of their voices.
One famous Celtic innovation was the war chariot.
However, the Celts greatest weakness was their disunity, which rendered them unable to resist the next mighty newcomers to the British Isles: the Romans.
The Celts in Britain remained relatively undisturbed, warring amongst themselves, until the mighty Romans under Julius Caesar invaded in 55 BC.
After subduing the Celtic tribes in Gaul (modern day France), an ambitious Caesar then planned to invade the mysterious island known to the Romans as “Britannia” in order to increase his prestige in back in Rome.
He crossed the English Channel and landed on the coast of Britain with a number of tough Roman legions, but after a short while withdrew back to Gaul.
The whole enterprise was a reconnaissance in force rather than a full blown invasion, but he nevertheless received applause back in Rome.
The following year, 54 BC, Caesar launched a much larger invasion which this time included a force of cavalry.
His strategy was to strike like lightening into the heart of the British Celtic tribes and inflict a decisive defeat on them before they could unite against him.
A bad storm however forced him to haul his ships from the sea to prevent them being sunk, giving the British enough time to form an army under the command and leadership of one of the first British heroes, the chieftain Cassivellaunus.
Cassivellaunusâ€™s strategy was to harass the Roman legions and prevent them from foraging for food, thus forcing them to quit their invasion.
Nevertheless, Caesar advanced to the River Thames and crossed it, despite it being heavily defended.
Cassivellaunus then ordered the four Celtic kings of Kent to attack Caesarâ€™s camp on the coast, but the attack was repulsed.
After the Romans defeated the attempted attack on the fleet and devastated his territories, Cassivellaunus surrendered.
Tribute was agreed and hostages were taken, after which the Romans withdrew back to Gaul.
The Romans were not to return to Britain for another 97 years.
The first Roman Emperor Augustus, taking power following Julius Caesar, planned a number of invasions of Britain, following in his adopted fatherâ€™s footsteps, but they were all abandoned.
Things changed, however, in 43 AD when the Emperor Claudius ordered the conquest of Britain.
Claudius raised an army of around 8 legions (40,000 men), placed them under a Roman general, Plautius, who then crossed the English Channel, swept inland, and defeated much furious Celtic resistance around the River Thames.
The Emperor Claudius wanted to be present at the final defeat of the British, however, and crossed into Britain with a force of elephants.
The Celtic city of Colchester was stormed by the legions shortly afterward and British resistance collapsed.
The British then surrendered and Britain â€“ actually the low land area known today as England – became a province of the Roman Empire, where it was to remain for hundreds of years.
Only the fierce northern Celts, called the Picts (based in Scotland), remained un-subdued.
The legions then spread out from Colchester and crushed the last remaining pockets of British resistance, such as at Maiden Castle hill fort in Dorset.
Native resistance to the Romans continued to simmer until 61 AD, when a full scale revolt broke out.
The king of a British tribe in East Anglia died, called the Iceni, in what is now Norfolk, following which the Romans decided to rule them directly.
They then publicly whipped his widow, called Boudicca, and raped his daughters.
This public humiliation sparked off a great revolt and many of the native British tribes joined forces and attacked several Roman strongholds, such as Londinium (what was to become the British capital city of London) and Colchester, both these towns being destroyed and 70,000 Romanised Britons killed.
The Roman army, numbering some 10,000, then met a British army of 100,000 somewhere in the West Midlands, and thanks to superior fighting skill, discipline and training, the Romans inflicted a crushing defeat on the native British.
Queen Boudicca then took poison to avoid capture by the Romans.
It was to be the last native revolt against the Roman occupation, and Britain now settled down to Roman rule for the next several hundred years.
The Roman occupation of Britain led to enormous cultural changes.
Very soon straight paved roads criss-crossed the country.
Aquaducts and bridges were constructed.
Cities were built which followed the Roman grid pattern.
They built sanitation and sewage systems.
Education and learning flourished.
Soon native British were being used as auxiliaries in the Roman legions, and at their height, the Romans stationed around 100,000 troops at York, Chester, Colchester and Carlisle.
Many of Britain’s major cities, such as London (Londinium), Manchester (Mamucium) or York (Eburacum), were founded by the Romans.
Now firmly entrenched in the lower part of Britain â€“ the countries now known as England and Wales â€“ the Romans began to turn their attention to the areas in the north, what is now modern Scotland.
In 78 AD the Roman governor Agricola successfully invaded northern Britain.
In 84 AD he defeated the Celtic Picts, but was then recalled to Rome, and the legions retreated to a more defensible line in southern Scotland along the Forth-Clyde isthmus.
The ferocity of the northern British Celts, the Picts, soon forced the Romans to retreat further to the south, into northern England.
When the Emperor Hadrian visited the province of Britannia around the year 120 AD, he ordered that a huge defensive wall be constructed across northern England, in line with his efforts to consolidate the Roman Empire.
This wall, still visible today, became known as Hadrianâ€™s Wall.
During the reign of the Emperor Antonius Pius the frontier was once again extended back to the Forth-Clyde isthmus, and a new wall was established, called the Antonine Wall.
Faced with revolts, the Romans soon withdrew back to Hadrianâ€™s Wall however.
From this point onwards, the Roman grip on Britain gradually slackened.
In 212 AD, the Emperor Caracalla granted all free inhabitants of the Empire citizenship of the Roman state, effectively making all native British Roman citizens.
This act led to a number of mixed-marriages between the Romans and the native British, which did not however have any effect on Britainâ€™s racial homogeneity.
In their homeland in modern day Italy, however, the Romans had been gradually losing their racial identity over hundreds of years of immigration and race-mixing, from all corners of the vast Roman Empire, until the original white Romans bred themselves out of existence.
With the Roman Empire starting to crumble, hordes of Germanic tribes started rolling westwards threatening all of Roman Western Europe.
In 312 AD the Roman Emperor Constantine officially converted to Christianity, a fledgling young religion then growing in popularity throughout the Roman Empire.
From that point onward Christianity spread to the province of Britannia, and was to remain the dominant religion until the arrival of the pagan Anglo-Saxons over a hundred years later.
During the last years of the Roman occupation of Britain, a British Christian missionary, called Patrick, travelled to Ireland with the intention of Christianising the Irish Celts, who were still pagans.
Patrick managed to turn Ireland into a Christian country and eventually became the patron saint of Ireland (St. Patrick).
During the 4th Century, Britain was subjected to an increased amount of raids and attacks from Germanic tribes based on the Continent, but the legions managed to hold on to the British Isles.
But by the year 410 AD, the Romans finally withdrew their legions from the province of Britannia.
The end of Roman rule in Britain left the whole British Isles vulnerable to the huge number of westward invasions and migrations of the Germanic Teutonic tribes, such as the Saxons, Vikings, Jutes, and Angles.