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Their legacy lives on in roads, amphitheatres and even our calendar. But one thing the Romans did not leave behind was their DNA.

The most detailed genetic analysis of Britain's past has failed to find any trace of genes from the Roman occupation of Britain.

Similarly, the Vikings may have a reputation for rape and pillage but the genetic evidence tells a different story.

The diagram above shows the European ancestry of each of the 17 genetic clusters found in the new genetic study of the UK. The Welsh were found to have DNA that dates back to the earliest settlers of Britain

For all their wild ways, they did not have enough babies with British women for their Danish DNA to survive today.

But while Britons lack Roman and Viking genes, we more than make it for it with French and German DNA.

The Oxford University study revealed that many English people are a quarter German.

On top of that, another 45 per cent of so of their DNA is French in origin.

The 'fascinating and exquisite' study involved analysing the genetic code of 2,000 people from the length and breadth of the British Isles and comparing the results to data on more than 6,000 people from ten European countries.

This revealed that 21st century Caucasian Britons can be separated into 17 distinct genetic groups.

Remarkably, many of these modern-day 'clans' are found in the parts of the country as the tribes and kingdoms of the 6th century – suggesting little changed in Britain for almost 1,500 years.

The people of Orkney are the most different, with 600 years of Norwegian rule leaving a lot of DNA behind.

The Welsh are the next more distinct from the rest of the UK. They have so much DNA from the first modern settlers, that they could claim to be the truest of Britons.

Even within Wales, there are two distinct tribes, with those in the north and south of the country less similar genetically than the Scots and the inhabitants of Kent.

The scientists found Caucasians in Britain can be divided into 17 genetic groups living in different parts of the country, as shown in the diagram above. Each group had varying amounts of European DNA in their genes

The Romans may have left their mark on Britain in many ways but their legacy has not survived in the genes

There is another clear north-south genetic divide, with the peoples of the north of England and Scotland having more genes in common with each other than with the inhabitants of the south of England.

Amazingly, clear differences can be seen between the inhabitants of Cornwall and Devon – with a genetic split that is almost an exact match for the modern geographical boundary.

West Yorkshire and Cumbria also have their own genetic heritage, moulded over the centuries.

The study, published in the journal Nature, did not find any obvious genetic footprint from the Romans or Danish Vikings, despite their having occupied large parts of Britain for hundreds of years.

The map of the UK on the left shows how the country can be divided into 17 distinct groups that have a striking relationship with geography. Each of the clusters is represented by a different symbol while the ellipses give a sense of the geographical range of each genetic cluster. The map on the right shows the regions of ancient British, Irish and Saxon control which relate to many of the modern genetic clusters 

However, this is not a reflection of a lack of virility. Instead, it seems that they simply weren't here in large enough numbers to have had enough children for their genes to live on today.

Study co-leader Sir Walter Bodmer said: 'You get a relatively small group of people who can dominate a country that they come into and there are not enough of them, however much they inter-marry, to have enough of an influence that we can detect them in the genetics that we do.'

His colleague Professor Peter Donnelly added: 'Genetics tells us the story of what happens to the masses.

'There were already large numbers of people in those areas of Britain by the time the Danish Vikings came so to have a substantial impact on the genetics there would need to be very large numbers of them leaving DNA for subsequent generations.

The study is the first detailed look at the genetic make up of Caucasian Britons and establish that they form 17 distinct groups. A stock photograph of a scientist examining the results of DNA sequencing is shown above

'The fact we don't get a signal is probably about numbers rather than the relative allure or lack thereof of Scandinavians to English women.'

Others said that the Danes may actually have been more attractive to local women because their habit of washing weekly meant they were seen as cleaner.

The Anglo-Saxons, in contrast, did leave a genetic legacy, with about 20 per cent of the DNA of many English people coming from the Danish and German invaders of 400 to 500AD.

Further DNA comes from earlier migrants, meaning many people in southern and central England are a quarter German.

The French have left an even larger footprint, contributing up to 45 per cent of the genes of many English people. This DNA did not come from the Normans but from much earlier.

THE  WEST COUNTRY NEIGHBOURS WHO HAVE REMAINED RIVALS

 They may be neighbours but they have never been close. Now, genetics could explain why.

The genetic map of the British Isles has revealed that the inhabitants of Cornwall and Devon are two distinct groups.

And, remarkably, the divide in their DNA is an almost exact match for the modern geographical boundary between the two countries.

In other words, people with Cornish genes tend to live on one side of the river Tamar, while those with Devon DNA are on the other.

Dr Magdalena Skipper, of the journal Nature, described the match as 'truly stunning'.

Oxford University researcher Sir Walter Bodmer said: 'It's an extraordinary result.'

The study also showed that the Cornish have fewer genes in common with the rest of the UK than the people of Devon.

Sir Walter said this can likely be explained by the Anglo-Saxons taking longer to reach Cornwall – and so contributing less DNA to the gene pool there than in Devon.

He added that there would also have been political and cultural barriers 'not to cross into Devon'

He said: 'People from Cornwall wanted to keep to themselves more.'

They may share a coastline, but the people living in Devon, shown left in the picture of Woolacombe, and in Cornwall, shown right in the picture of Mawgan Porth, were found to make up two distinct genetic groups

It includes contributions from some of the earliest modern Britons who arrived after the last Ice Age and mystery set of migrants who came here after these first settlers but before the Romans.

Other countries to contribute genes to 'English DNA' include Belgium, Denmark and Spain.

The modern Britons studied were chosen because their grandparents had all been born near each other.

So while their DNA was analysed, the results were really providing information on Britain at the end of the 19th century.

Britain today is much more genetically diverse that 125 years ago but the same technique could be used to read someone's DNA and work out which parts of the UK their ancestors came from.

The study took into account the fact that Roman soldiers came from many different countries and not just Italy.

So is thought that their DNA wasn't found simply because not enough of them settled here.

Sir Walter said: 'At that time, the population of Britain could have been as much as one million, so an awful lot of people would need to arrive in order for there to be an impact.

'You can have a huge impact culturally from relatively few people.

'There is no evidence of a Roman genetic signature but there is evidence of what the Roman's achieved.'

Dr Michael Dunn, of the Wellcome Trust, which funded the study, said: 'These researchers have been able to use modern genetic techniques to provide answers to the centuries' old question – where we come from.

'Beyond the fascinating insights into our history, this information could prove very useful from a health perspective.

'Building a picture of population genetics at this scale may in future help us to design better genetic studies to investigate disease.'  

VIKINGS PILLAGED BUT APPEAR NOT TO HAVE DONE MUCH RAPING

The Vikings may have a ferocious reputation for raping and pillaging their way across the British Isles, but it appears they may not have been as sex mad as was believed.

Analysis of thousands of DNA samples from the UK, continental Europe and Scandinavia revealed a surprising lack of Viking genes in England, despite the Norsemen once occupying much of the country. 

Even in Orkney, which was a part of Norway from 875 to 1472, the Vikings contributed only about 25 per cent of the current gene pool.

It suggests that the Vikings mixed very little with the indigenous population they initially terrorised and then conquered. 

The international team led by scientists from Oxford University and the Wellcome Trust wrote in the journal Nature: 'While many of the historical migration events leave signals in our data, they have had a smaller effect on the genetic composition of UK populations than has sometimes been argued.

'In particular, we see no clear genetic evidence of the Danish Viking occupation and control of a large part of England suggesting a relatively limited input of DNA from the Danish Vikings and subsequent mixing with nearby regions, and clear evidence for only a minority Norse contribution (about 25 per cent) to the current Orkney population.'

The Vikings, from Norway, Sweden and Denmark, carried out extensive raids and occupations across wide areas of northern and central Europe between the eighth and late 11th centuries.

The Vikings, pictured above in the hit TV series, had a reputation for pillaging and vicarious sexual appetites, but it seems they did not sire many children during their raids and conquests in the British Isles

Danish Vikings in particular took over large parts of England, eventually settling in an a region stretching from Essex to County Durham which was ruled by 'Danelaw'.

The findings support previous research from the University of Oslo suggesting that Viking men were family-orientated and not particularly bothered about the British women they conquered.

Rather than Viking raiding parties consisting wholly of testosterone-charged men, researchers found that significant numbers of women, and possibly whole families, travelled on the longboats.

DNA extracted from 45 Viking skeletons showed that women played an integral part in establishing settlements in the UK.

Sir Walter Bodmer, from Oxford University, said the lack of Viking DNA may have largely been to do with numbers.

He said: 'It's important to emphasise that when you get that mixture it's very much a question of the ratio of the people who come in and the indigenous population.

'However active the incoming males may be if there are not that many of them, they can't actually penetrate a large number of the local women.'