NOT ONLY WAS THE weather miserable, with frequent rains and mists, Britain was also not worth having. The phenomenal expansion of the Roman Empire was driven by what Tacitus called the pretium victoriae, the ‘wages of victory’ or how much wealth could be extracted from the defeated by the conquerors. A sodden landscape, half-hidden by cloud, producing nothing more exciting than cattle, corn and a few substandard pearls, the place was thought simply incapable of delivering a decent return on all that outlay of men, materials and money. Roman commentators dismissed a conquest of Britain as making no sort of economic sense.

But it was good politics. Just as it appeared to Herodotus, Britain seemed to Rome and Romans to be a long way away, far to the cold and barren north, on the edge of the known world. That was the political point. When Julius Caesar courted near disaster with his expeditions in 55 and 54 BC, it was precisely because it was an island at the limits of the world that his daring exploits created a sensation in Rome. Twenty days of feasting and public thanksgiving were ordered by the Senate, thrilled that the Empire could reach to the ends of the Earth and defeat the unimaginable savages who lived there. Glory was the attraction – not profit.

When Claudius was set on the imperial throne by the Praetorian Guard after the inevitable assassination of the crazy Caligula in AD 41, there was a pressing need for glory. Plots and attempted coups flickered around the court of the new emperor and his grasp on authority seemed to be slackening. Military success would persuade waverers and it was decided that a conquest of Britain would silence criticism. To extend the Empire to the edge of the world? To outdo the great Julius Caesar? Just what Claudius needed. And maybe the pearls were better and maybe there were seams of gold and silver in the misty mountains? An added attraction was that Britain was a good reason for breaking up a potentially dangerous concentration of crack troops stationed on the Rhine frontier. It was a ready-made army for an ambitious general considering a coup. The legions on the German borders would no longer be bored, staring at the impenetrable forests, patrolling beyond the river, searching for phantoms amongst the trees. Britain beckoned.

In the summer of AD 43, led by Aulus Plautius, Rome triumphed in the south of England. When the good news reached the imperial court, the invasion force was commanded to halt on the line of the Thames, consolidate and wait for Claudius. In order to extract full propaganda value, the emperor would be seen at the head of his legions, in his armour, marching with them on the road to glory. To add to the spectacle, he brought elephants, war elephants – creatures never before seen in Britain – and, as the British kings retreated, awed and ultimately defeated, Claudius and the many senators brought along to serve as witnesses entered Camulodunum, modern Colchester. It was the royal centre of the Catuvellauni and their king, Cunobelin, Shakespeare’s Cymbeline. In his moment of stage-managed triumph, having gone further than Caesar, Claudius was not to know that, while the south of Britain was won at Colchester, it would almost be lost there only a few short years later.

Eleven kings arrived at Cunobelin’s old capital to make submission, according to a triumphal arch erected in Rome, and later the emperor took the title of Britannicus. Amongst those British kings who bowed to Rome was the king of Orkney, his arrival being a cause of yet more amazement at the reach of this new and dynamic emperor. A historian called Eutropius wrote, ‘Claudius added to the Empire some islands lying in the Ocean beyond Britain, which are called the Orkneys.’ It was a high-water mark.

Careful not to overextend, the legionary legates marched against only those kingdoms that would not submit. The future emperor, Vespasian, led the II Augusta west into the territory of the Durotriges and laid siege to the vast, sprawling hill fort of Mai Dun, Maiden Castle. The beautifully undulating banks and ditches did provide a defensive shelter as, for once, the sacred precinct took on a military purpose. After batteries of siege engines had bombarded the stockade with stones and huge javelins, the Romans broke in and destroyed the makeshift garrison. Elsewhere, more peaceful methods were deployed. North of Colchester lay the lands of Prasutagus, king of the Iceni, and he had come to terms with Rome, adopting the status of a client kingdom.

By AD 60, much of the south of England had fallen under the control of the invading legions. In his Annals of Imperial Rome, Tacitus listed a series of wars against British kings and made much of the story of Caratacus. For nine years this king of the Catuvellauni, the son of Cunobelin, had led a determined resistance. What is striking is the degree of unity and military cooperation across Britain. Even though he had lost his own kingdom (perhaps fleeing with an elite war band) in the early years of the conquest, Caratacus was accepted as a general by those kindreds who refused to submit. This implies a degree of cultural continuity, a shared language and shared beliefs.

Some time around AD 50, Caratacus’s army faced the brigaded legions on ground of his choosing in North Wales, probably at Llanymynech Mountain on the modern border with Shropshire. After the discipline and tenacity of Rome’s professionals inflicted a surprise defeat, Caratacus fled for sanctuary to Queen Cartimandua of the Brigantes. Tacitus believed this federation of kindreds to be the largest and most powerful polity in Britain. It compassed both sides of the Pennines, modern Yorkshire, Lancashire, much of Cumbria, Durham and Northumberland south of the Tyne. But, instead of using the strength of the Brigantes in the struggle with Rome, Cartimandua had become a client like Prasutagus of the Iceni and she had Caratacus arrested and handed over to the Romans. Paraded through Rome in chains, he was pardoned by the Emperor Claudius but he never saw Britain again.

Resistance continued. In his Annals, Tacitus recorded that the kindreds of Wales and the Silures of the south in particular were exceptionally stubborn. And Venutius, the consort of Cartimandua, led a breakaway Brigantian army reinforced by help from outside. It seems that the kings of what is now southern Scotland were being drawn into the fight against Roman domination. Perhaps they came to understand that imperial policy at that time favoured the conquest of the whole island. Certainly what happened AD 60 suggests as much.

Suetonius Paulinus, a new governor, fresh from Rome and no doubt with a clear grasp of the emperor’s wishes, led the legions to a corner of Britain that could easily have been bypassed and had little strategic significance. Here is the relevant passage from Tacitus’s Annals describing the assault on Anglesey:

Even across two millennia, Tacitus’s double standards raise an eyebrow. Roman armies regularly slaughtered captives in their thousands or sent them to suffer humiliating deaths in the arenas of their cities for the amusement and titillation of citizens. The Empire shed far more blood for much longer than Druid priests did. Nevertheless human sacrifice appears to have been part of British religious practice both before and after the arrival of the legions.

Across northern Europe, in Ireland, Britain and Scandinavia, more than a hundred bodies dating from 600 BC to AD 400 have been retrieved from peat bogs, preserved by their anaerobic properties. Many show evidence of a ritual death. Perhaps the clearest signs were found on a body discovered in Cheshire known as Lindow Man. After a post-mortem, scientists concluded that he had been an aristocrat. His hands showed no evidence of manual work and the man was young and healthy. Perhaps he was himself a priest or his status in itself recommended him as a sacrificial victim.

Lindow Man’s death was protracted and almost certainly excruciating – there was no evidence that he had been given a drug. Almost certainly surrounded by priests and perhaps a large congregation gathered to witness an event of immense significance, the young man was first poisoned and then beaten. He was hit on the head with an axe but the blow did not kill him. He lived to be garrotted and have his throat cut. When the priests placed his naked body in Lindow Moss to drown, it is possible that, even at that moment, he was still alive.

The victim suffered a multiple death, a rite sometimes known as the triple death, and this savagery survived in Druidic traditions well into the Dark Ages. Merlin or Myrddin was said to have been hit on the head, garrotted and drowned in the River Tweed.

Suetonius Paulinus’s attack on Mona appears to have been emblematic. Julius Caesar recognised the political power of the Druidic priesthood when he campaigned in Gaul and recorded their use of groves as places of worship and sacrifice, the places destroyed by soldiers on Mona after the battle at the Menai Straits. He also believed that the cult originated in Britain and had been imported into Gaul. Such was the power of Druids that it was said their arrival could stop a battle. And Caesar’s account of his campaigns, Commentarii de Bello Gallico, was very influential.

In any event Mona, the Sacred Isle, appears to have been the centre of the cult. At Llyn Cerrig Bach, a small lake in the west of the island, metalwork from all over Britain was ritually deposited, probably by pilgrims. Tacitus commented that Mona had given sanctuary to many refugees, displaced people drawn to the island because of its sacred power. There the gods would protect them.

As the legions swept aside the curses of the Druids and the screams of the black-robed Furies with their spiked, limewashed hair and hacked down the groves of the holy sanctuary, trouble was stirring on the other side of Britain.

Two Roman statutes of the second century BC, the lex Porcia and the lex Sempronia, gave, amongst other things, directions for the public flogging of non-citizens. They were to be stripped naked and bound face first to a post in a place where it was convenient for a crowd to gather and watch. Ancient justice had always to be seen to be done. Whips often had small pieces of metal or bone attached to their tips so that blood would be drawn and the backs or buttocks of prisoners badly flayed. Screams and extreme suffering were also understood as important parts of the judicial spectacle. Flogging was often a prelude to crucifixion and the pattern of punishment meted out to Christ followed the tenets set out in the lex Porcia and lex Sempronia.

Possibly at Thetford, where the remains of an Icenian royal palace have been found, Queen Boudicca was led to a whipping post, stripped, tied to it and flogged. Her crime had been to object. Boudicca’s husband, King Prasutagus, had died and, in his will, bequeathed half of his estates and treasure to the Emperor Nero and half to his wife and two daughters. It was a device often used by Roman aristocrats who hoped that, by giving the emperor a stake in them, the conditions of their wills would be carried out and have the authority of the state to enforce them.

In AD 60, the administration of the province of Britannia was run by the procurator, Decianus Catus, and, while the governor was away campaigning in the Druid sanctuary of Mona, he took matters into his own hands. Catus’s initiative was to have catastrophic consequences. Ignoring the terms of Prasutagus’s will, he treated the kingdom of the Iceni like conquered territory, looting treasure, taking over estates and evicting aristocrats from their property. When Queen Boudicca resisted this patent injustice, she was humiliated by a public flogging and her daughters, the royal princesses, were raped by Roman soldiers. It was impossible for Catus to understand that, in Celtic society, women had status and could rule. In Rome, women had the same legal standing as children.

It was an incendiary moment. The kingdom flared into rebellion as the Iceni were joined by the Trinovantes to the south and Boudicca quickly mustered a huge army. She immediately led it south to Colchester. The town was burned to the ground as more war bands rushed to join the rolling momentum of the uprising. When news reached Suetonius Paulinus, the legions hurried south-east and, from Lincoln, part of the IX Legion marched to meet the Queen’s growing host. Under the command of Petilius Cerialis, the infantry of the IXth were overwhelmed and slaughtered. With only his cavalry, the tribune fled to take refuge at the fortress at Longthorpe, just to the west of Peterborough. The province of Britannia teetered on the edge of extinction as the thunder of rebellion boomed out over the land.

Meanwhile, Suetonius Paulinus had reached London at the head of an advance party but, when news of the defeat of Cerialis came, a difficult decision had to be made. Opting to regroup with his main force of infantry, still marching down Watling Street from Mona, the governor abandoned London. Tacitus takes up the story:

Stiffened by their habitual discipline and steeled by the certain knowledge that defeat meant annihilation, the legions drove into the vast native army and shattered it. Hemmed in by the wagons of their own camp followers, the huge host was trapped in a blood-soaked killing field. Boudicca and her daughters took poison and, after the battle, Suetonius Paulinus embarked on expeditions of vengeance. The territories of the Iceni and Trinovantes were plundered and burned and those kingdoms that had remained neutral were similarly punished.

What fuelled the uprising (sparked by Boudicca’s humiliation) was the threat of slavery and destitution – even in peacetime. Here is Tacitus again:

They particularly hated the Roman ex-soldiers who had recently established a settlement at Camulodunum [Colchester]. The settlers drove the Trinovantes from their homes and land, and called them prisoners and slaves. The troops encouraged the settlers’ outrages, since their own way of behaving was the same – and they looked forward to similar licence for themselves.

Colonisation of this sort was common in the Roman Empire as soldiers completed their terms of service and decided to settle in the provinces. Over the four centuries of Britannia, many veterans were given land, married native women and introduced their DNA. But it is very difficult to identify its traces with any certainty.

By the time of the Boudicca uprising in AD 60, the Roman army was no longer a force of citizens of Italian origin. Augustus, the first and perhaps most clear-sighted emperor, created a highly professional standing army of twenty-eight legions, each with approximately 6,000 men. The number of auxiliary troops was about the seme, making a total complement of 336,000. The length of legionary service was extended from six to twenty years. What lay behind Augustus’s reforms was, of course, a series of political judgements. The old republican armies of citizens and assorted levies had developed intense loyalties to their generals, the aristocrats who rewarded them – men like Pompey, Caesar and Mark Anthony. By insisting on an oath of allegiance to the emperor alone, Augustus loosened these bonds and, at the same time, recruitment was widened well beyond Italy to include the provinces. By AD 100 and the reign of Trajan, the ranks of the Roman army were mostly filled by men from northern Europe and only about 40 per cent originated around the shores of the Mediterranean. In AD 200, 80 per cent of the army was from the northern and eastern provinces.

By its ruthless nature, the huge trade in slaves in the Roman Empire moved large numbers of people great distances. And, as slaves gained their freedom, often settling in places far from where they were born, the ethnic make-up of the empire became very mixed. Tacitus sniffed, ‘[I]f freedmen were marked off as a separate class, then the scanty number of freeborn would be evident.’

What all of this means is a picture of great complexity and unclarity. If half of all the soldiers who settled in Britain as colonists in places like Colchester were from northern Europe, their DNA will be hard to distinguish in a native British population with pre-existing close links to the opposite shore of the Channel and across the North Sea. And certainly a Mediterranean input in the 400 years of the province of Britannia is impossible to identify with any certainty from current data.

It is possible to count how many lineages in Britain which are common and diverse in Italy and in the Mediterranean generally and use this calculation to give an idea of maximum Roman input. It can be as much as 10 per cent in the south-east of England. However, the same lineages all arise in the Near East and were also carried to Britain by the early farmers fanning out from the Fertile Crescent. Most geneticists consider the latter scenario to be much more important if for no other reason than the fact that many fewer people lived in Britain in the centuries around 3,000 BC and so the effect of the earlier immigrants was concomitantly greater.

If that is true for southern Britain, then it must be emphatically the case in the north as a territory that was only fleetingly and occasionally part of the empire. The maximum figure is 2 per cent but the actual number is likely to have been very much lower. What did the Romans do for Scotland’s DNA? Almost certainly very little.

The Iceni uprising appears to have galvanised imperial strategy, such as it was, in Britain. Over the next twenty years, the legions tramped northwards, first subduing the great trans-Pennine kingdom of the Brigantes and then, under the command of Tacitus’s father-in-law Agricola, striking deep into Scotland. It seems that the conquest of the whole island of Britain was envisaged. At Mons Graupius in Aberdeenshire, the Romans overcame the Caledonian Confederacy led by the first-named of our ancestors, Calgacus. The men with the red-gold hair and massive limbs described by Tacitus were, like Boudicca’s host, no match for the grim, close-quarter fighting of the tight legionary formations and the dash and bravery of their auxiliary cavalry.

With the accession of the Emperor Domitian on a dark tide of rumours about the poisoning of his brother Titus, the army in Britain was ordered to pull back from Scotland. Resources were urgently needed elsewhere and retrenchment became the guiding strategy. In order to secure the northern frontier in Britannia, the provincial government built the Stanegate, the Stone Road, between the eastern fort at Corbridge that guarded the crossing of the Tyne and the western fort at Carlisle that watched the Solway and the ford over the Eden. After the withdrawal from Scotland, more forts were added at half-day marching intervals and, for the moment, Rome seemed content to patrol and be watchful on its most northern horizon.

When Hadrian decided to consolidate further and more permanently, building his mighty wall only a mile or so beyond the line of the Stanegate, the military logistics involved were staggering. More than 30,000 soldiers were deployed to source and gather materials, transport them to the site and build. A substantial garrison was posted along the length of the Wall and they were to remain there in various guises and strengths for three centuries. Archaeologists have discovered precious information about precisely who stood on the northern rampart watching for trouble rumbling out of the north. From inscriptions and letters, it is clear that there were units from Tungria and Batavia, themselves frontier peoples from the Rhine delta and what is now Belgium. Syrian archers were based at the fort at Carvoran and a cohort of Spanish cavalry garrisoned the large base at Maryport, part of the sea wall that ran down the Cumbrian coast – two northern European regiments and two from the Mediterranean stationed on the chilly Solway shore.

When Hadrian’s successor, Antoninus Pius, required a fanfare of military glory to usher in his reign in 138, the frontier was briefly moved up to a new wall between the Forth and Clyde, across the narrow waist of Scotland. The Tungrians and Syrians were joined by Thracians, Gauls, the Baetasians from the Netherlands and a cohort recruited in northern Spain. It was an imperial policy to post provincial units some distance away from their origins. Their tour of duty in Scotland was brief and in 157 the line of the frontier was once again pulled back to Hadrian’s Wall.

If imperial strategists hoped that consolidation would bring peace, they were quickly disappointed. There was war in northern Britain in 161 and again in 180 when native armies crossed the Wall, massacred a Roman force and killed the governor. The crazy Commodus had succeeded his father Marcus Aurelius and the astute British kings probably hoped to take advantage of weakness and uncertainty in Rome.

Britannia remained vulnerable even though a new governor managed to drive out the invaders. Walls were built around the towns in the south and the Wall garrison strengthened. While Gaul and Spain were fully integrated into the empire, there is a sense that a version of apartheid in Britain lingered. From a population of two to three million, only 10 per cent lived in the hundred or so towns and maybe 50,000 on the villa estates in country districts. When the garrison of the Wall and the legionary fortresses and the inhabitants of the vici, the villages attached to them, are taken into account, it may be that only a fifth of the total population of Britannia might be seen as Romano-British. In the countryside the vast majority continued to speak dialects of Old Welsh and to live in a Celtic cultural atmosphere. By contrast, the native languages of Spain and France were dying out and cities were developing. It may be that the central problem for the governors of the province was that, in Britain, Rome simply did not catch on.

After Commodus’s inevitable assassination, Septimius Severus established himself. Campaigns in the east, in Parthia, prompted more opportunism from northern kings. The governor of Britannia was forced, in 197, to buy peace with large bribes for the Caledonii and the Maeatae. The historian Dio Cassius had heard of these two powerful peoples:

The two most important tribes of the Britons [in the north] are the Caledonians and the Maeatae; the names of all the tribes have practically been absorbed in these. The Maeatae dwell close to the wall which divides the island into two parts and the Caledonians [are] next to them. Each of the two inhabit rugged hills with swamps between, possessing neither walled places nor towns, but living by pastoral pursuits and by hunting.

Dio meant the Antonine Wall and one of the swamps was the long, largely unbroken stretch of Flanders Moss, five miles wide and beginning at the foot of Stirling Castle rock and reaching as far west as Aberfoyle. Place-names remember the Maeatae and confirm their location next to the wall. Dumyat rises north of Stirling and it derives from Dun-Maeatae, the fort of the Maeatae. Next to it is Myerton Hill and to the south, near Falkirk, is Myot Hill, perhaps a southern boundary. The kingdom lasted for many centuries. In the seventh century, St Adomnán recounted a famous battle between the men of Argyll led by King Aedan macGabrain and the Miathi. And it seems that their DNA may also have endured.

The rare variant of S145-str43 is found in only 79 bearers in online databases which hold details of up to 200,000 people. Of these, 53 know where their father lines originated – 27 in Scotland, 16 in Ireland and ten in England. The distribution in Scotland is fascinating because it is so localised and it may be that the ghosts of the Maeatae still flit around Stirling. Most men in Scotland with S145-str43 came from Doune, Dunblane, Fintry and Port of Menteith. The dating is right and the clustering more than suggestive. The Irish distribution is overwhelmingly in Ulster strongly hinting that bearers arrived during the time of the plantations in the sixteenth and seventeenth centuries and some even share Scottish surnames. There are no markers in the Borders or Lothian but ten in England. A little more history will supply an explanation.

When Septimius Severus at last arrived in Britain in 208 to deal with the threat of the northern kings, he did nothing by half measures. A huge army of 40,000 men – the largest ever seen – marched up Dere Street into Scotland. The Maeatae and Caledonii sued for peace immediately and were ignored. Severus pressed on, scorching the earth, burning and plundering – but resistance did not shrivel. In 211, the kings of the northern kindreds mustered their armies once more. But then fate intervened. At the legionary fortress at York, Severus died and his son Caracalla seized the throne, later killing his brother. Needing to make all haste to Rome to secure a fragile hold on power, he quickly came to terms with the Maeatae and the Caledonii. Usually, this involved the handover of aristocratic hostages to guarantee good behaviour. Such people were often allowed small retinues – and it may just be that these bearers of S145-str43 were accommodated at one of the large forts on Hadrian’s Wall. Two of their descendants can trace father lines to Northumberland and another to North Yorkshire. Such links are a stretch, without doubt, but the Scottish data is much more robust. Statistically, this cluster is not insignificant – about 30,000 or 0.6 per cent of all Scottish men carry the marker. It seems that across 2,000 years, the descendants of one of the most warlike lost kingdoms of the north have survived.

The century after Severus’s wars appears to have been relatively peaceful despite a rapid turnover of emperors in Rome. Between 235 and 284, 15 reigned briefly and many other pretenders made attempts on the throne with the sporadic and often fickle support of various provincial legions. Against this background of instability, Britain eventually broke away. Carausius, the admiral of the Classis Britannica, the British Fleet, proclaimed himself Emperor of Britain and part of northern Gaul in 286. Seven stormy years later, he was assassinated by the unlikely figure of the civil servant Allectus, his Financial Secretary. During his unsteady reign, the kings in the north began to make plans.

In 296, war bands crossed the Wall and raided far to the south, even attacking the legionary fortress at Chester. An alarmed Roman historian described these insurgents as particularly ferocious and he gave them a new name. Probably first coined as a soldiers’ nickname, they were called the Picts – the Painted or Tattooed People. It was a dramatic entrance for one of the great kindreds, the makers of much of Scotland’s early history.

While there are no texts and no one could now compile a sentence, whispers of a Pictish language have survived in placenames, particularly those with the prefix pit- or pett-. In names like Pittodrie in Aberdeen and Pitreavie in Dunfermline, its distribution stretches down the eastern coasts of Scotland to the Forth – pit means ‘a portion or piece of land’ and is often attached to a personal name in order to identify the owner. For example, Pitcarmick in Perthshire was originally ‘Cormack’s portion’ and Pitkenny in Fife was ‘Kenneth’s land’. The distribution of pit-place-names fits closely with the locations of another Pictish legacy. Their wonderful, magical symbol stones are to be found mainly from the coastlands of the Moray Firth down to Fife and sometimes beyond. The names of their provinces or minor kingdoms and lines of Pictish kings have also been preserved but there are very few written records of anything that might be called history. And then, in the ninth century, the Picts appear to disappear.

The beautifully carved but enigmatic symbol stones, the gorgeous jewellery and their sculpture marked the Picts out as a distinct, even exotic culture. But the lack of ethnic evidence of their history has turned an enigma into a mystery. One of the most famous enquiries was entitled The Problem of the Picts. Historians have speculated that they were invaders whose culture flourished and then dissolved into nothing, leaving no discernible political or social legacy.

Geneticists can at last offer some clarity and resolve much of the mystery. DNA analysis reveals that the Picts have not disappeared – they are, in fact, still here, living anonymously amongst us. They look like us, live like us and are probably entirely unaware of their extraordinary history, their culture and great art. A marker has been identified that is essentially unique to Scotland and very rarely found anywhere else (there is some small leakage in Ulster, probably as a result of the plantations and a little spreading to the north of England). It is known as R1b-str47 or R1b-Pict and around 10 per cent of Scottish men carry it. In our cities, towns and villages, 250,000 Picts are quietly going about their daily lives.

The distribution of the marker broadly matches Pictish territory and, where later incursions such as the Dalriada Gaels and the Vikings overlaid it, the numbers are diluted. It is well represented in the east of Scotland above the Forth but much less so in the Northern and Western Isles. Skye is an interesting exception. Five early symbol stones have been identified on the island and it may well be that Gaelic arrived there relatively late.

R1b-Pict is at least 3,000 years old and possibly even older and is a subgroup of S145, the marker associated with the Celtic-speaking populations of the Isles. It looks as though the marker developed among the earlier peoples who settled in Scotland and, if recent research is borne out, its bearers are descendants of the first farmers. Therefore, it should be seen as a pre-Pictish marker but one that would have been common amongst the Picts.

The Picts were, of course, related to the British to the south and the Irish to the south-west and their sharing of the S145 marker at high frequencies underpins this. While four centuries of Rome seems to have made little impact on the DNA of Britain, what happened after the collapse of the province after 410 certainly changed our genetic make-up. Slowly at first but with gathering momentum, another group of invaders sailed to Britain and ultimately to Scotland.

Sea raiders from the North Sea coasts of the North German Plain, particularly from the area between the mouths of the Elbe and the Weser and the southern neck of the Danish peninsula, had been attacking the western empire since the third century. Not only had they rasped their boats up on British beaches and plundered settlements for anything portable (including people), they had also raided as far south as the Bay of Biscay. A sophisticated, literary Roman landowner Sidonius Apollinaris was appalled and wrote in the fifth century that these Angles and Saxons were the most brutal, savage barbarians yet seen in the west. When they were about to set sail for home, they were in the habit of offering a sacrifice to their bloodthirsty gods by drowning or crucifying one in ten of their captives thus ‘distributing the iniquity of death by the equity of lot’.

The imperial administration in Britannia had been dealing with Anglo-Saxon and other Germanic pirates for most of the fourth century and had built an impressive chain of coastal forts from Brancaster in Norfolk round to Porchester on the Channel shore. For genetic historians the battle lines are less clearly drawn. The garrison of the province had long counted Germanic soldiers amongst its units. At Housesteads Fort on Hadrian’s Wall, altars have been found dedicated to gods native to Frisia in north-western Holland. One inscription suggests another Germanic group from even further to the north. The Numerus Hnaudufredi translates as ‘Notfried’s Own’ and sounds like a prince and his war band conscripted into the armies of the empire. Much later, in 367, a combined invasion of the province by the Picts, the Scots, a mysterious people probably from the Western Isles known as the Attacotti, the Franks and the Saxons overran Britannia. They attacked the coastal defences, the forts of the Saxon Shore, and killed the imperial forces defending them and their commander. His name was Fullofaudes, a German.

The blurred genetic picture of Germans already in Britannia fighting another set of Germans trying to settle there is matched by an equally unclear sequence of events. It seems that in 406 the army in Britain backed the claims of a usurper-emperor and all that is known of him is his name, Marcus. Very quickly he was replaced by another usurper – this time, a native British candidate called Gratian. And then he, in turn, was removed by Constantine III who was said to have been only a low-ranking soldier.

Meanwhile, the empire was beginning to crumble. After the Rhine froze on the last day of 406, it is thought that more than 70,000 barbarians slithered across the ice and entered Gaul, rampaging, looting, killing and causing chaos. It was a number large enough (and with a datable arrival) to leave a genetic legacy – unlike the small groups of men in small boats who landed on British shores. In 407, Constantine III led what remained of the garrison of Britannia to Gaul to deal with the insurgents. The province was left very vulnerable when a large force of Saxons attacked the eastern coasts a year later. This was a turning point and, in a rare moment of precision, the historian, Zosimus, summed up what happened:

The immediate impact of this break with the imperial past was not clear. Money must gradually have ceased to circulate. Since there had been no mint in Britain for a century, cash to pay soldiers and administrators had to be imported from across the Channel. It reached the length of the province and even beyond Hadrian’s Wall. In a field near Kelso in the Scottish Borders, hundreds of Roman coins have been found. The strong suggestion is that they were pay for an outlying unit based in a fort on the mound now occupied by the ruined medieval castle of Roxburgh. Most of the coins are small bronze radiates and some date very late, shading into the fifth century and the reign of the Emperor Honorius, almost to the very last days of the imperial province. The radiates are not in themselves valuable and appear to be evidence of a money economy operating on the banks of the Tweed around 400. Whenever the metal detectorists who found the coins see a new one glinting on the furrows of the ploughed field where most have been turned up, they marvel at the reach of Rome even in its dying days in the west. And when they pick up something dropped by an imperial soldier, they feel a shiver of contact with the long past.

That soldier may have been a German in the pay of the Empire, perhaps hoping for greater rewards as a supporter of a British usurper. Barbarian kings regretted the ultimate fall of Rome, engulfed by the chaos of assaults on the imperial throne by usurpers. Athaulf, the successor of Alaric the Goth who famously sacked Rome in 410, mourned the passing of a lawful society and feared the anarchy that would follow the takeover of the west by barbarian peoples. These kings saw the empire as a career opportunity rather than as a victim to be destroyed but, once the process of disintegration was underway, it became unstoppable.

By the middle of the fifth century, Kent was a Jutic kingdom and Angles and Saxons had begun to settle elsewhere along the coasts of the North Sea. One of their most famous footholds was at Bamburgh, now the site of an immensely impressive restored castle. What may have initially been a base for raiders (the beach allowed boats to be easily dragged up above the high-tide mark and the castle rock offered refuge as well as being a rare seamark along a flat and relatively featureless shore) became the kernel of a great kingdom. By the middle of the sixth century, Bernicia was beginning to emerge.

The name itself is an insight into how this fascinating kingdom came about. Bernicia derives from Bryneich or Berneich and it is an Old Welsh name that means something like ‘the land between the hills’. Given the location of Bamburgh and its closeness to the wide Tweed basin lying between the Cheviot Hills to the south and the Lammermuirs to the north, it looks as though the kings of Bryneich ruled a prime tract of fertile farmland, precisely what was needed to sustain political power in the sixth century.

The rolling fields of the Merse (the name still used for southern Berwickshire and cognate to Mercia which means ‘borderlands’) were very desirable. Before the age of improvement in the eighteenth and nineteenth centuries, drainage was almost entirely natural, and while flat river valley bottoms are now valued for intensive agriculture, they were often very boggy and unsuitable for raising crops or pasturing beasts. In contrast, the gentle descent of the landscape of the Merse to the banks of the Tweed, with its free-draining fields in undulating and sheltered countryside, was perfect for early farmers. To the eye of a sixth-century landowner, this was a place where rich harvests could be reaped.

The Merse was also part of the Old Welsh-speaking kingdom of Gododdin, with its bases on Edinburgh’s castle rock, Traprain Law in East Lothian and probably Eildon Hill North and Yeavering Bell at the eastern edge of the Cheviot ranges. This loose and ill-defined polity pre-existed the collapse of Britannia, having lain to the north of Hadrian’s Wall for centuries, and it grew from the kindred known to Roman mapmakers as the Votadini. When it came into violent contact with the Bernicians, it would emerge from the shadows of history for a brief and bloody moment.

Ida, son of Eobba, was the first king to rule from Bamburgh. In his Ecclesiastical History of the English People, written in the years around 730, the Venerable Bede noted, ‘In the year 547, Ida began his reign, which lasted for twelve years. From him the royal family of the Northumbrians derives its origin.’ While clearly a very great historian and a pioneer who checked his sources and actively sought information, Bede was not immune from the pressures of politics. His aim was to compile a history of the English people, the Angles, the Saxons, the Jutes and others who had overrun England by the time he sat down to write. He was not much interested in the natives, the vast majority of the population. Instead, royal ancestry, legitimacy and continuity were a central part of his purpose and Northumbrian authority and its hegemony over the rest of England was portrayed as a pleasing and civilised continuation of Roman rule.

There are few alternative written sources for the Dark Ages in Britain and one of the most fascinating and maddening is Nennius’s History of the Britons. Amongst much myth-history and tales of giants and dragons, there is a series of related passages known as the North British section. Scholars have argued that these are fragments from a lost chronicle of the northern kingdoms of the fifth and sixth centuries. It may have been the work of monks at Whithorn in Galloway or Glasgow. In any event, it states that ‘Ida joined Din Guauroy to Berneich’. Din Guauroy was the original Old Welsh name for the fort at Bamburgh (renamed after Ida’s queen, Bebba) and Berneich the earlier version of Bernicia. There is none of the usual language of conquest or war in either Nennius or Bede and it may be that Ida did indeed effect the union of two kingdoms. Perhaps he led a small but vigorous war band who established their leadership of the men of neighbouring Berneich, a Celtic kingdom, perhaps a southern or satellite province of Gododdin. From this union flowered Northumbria, the first great power of the Dark Ages in northern Britain.

Despite its political prowess and cultural achievements, there is very little genetic evidence for significant Anglian immigration in the north or in southern Scotland. But that is not to say that there is no signal at all. The S21 group is more frequent among south-eastern Scottish Y chromosomes and, in fact, a subgroup labelled S29 is found there – and it has not been detected anywhere else in Scotland. It is very much an English marker in the British Isles, concentrated in the east of England and also spread widely on the North European Plain. Tantalising hints like this do suggest that there are traces of Anglian DNA. Most other Germanic genes from the period are, at present, difficult to distinguish from earlier arrivals and more definite estimates will have to wait for more markers to be identified in the future. However, the signal in the Lothians and the Borders is much lower than that in East Anglia. Quite probably, therefore, a huge influence was exerted by a small group of powerful incomers over a large native population. When the British ruled the subcontinent of India and Pakistan, they did so with a tiny garrison and, although they were better equipped, the natives could have grouped together and overcome them. But they did not.

The most likely solution to the mystery of Anglian domination is fusion. Encouraged by Bede, the Arthurian stories and modern historians reading history backwards, we too easily see a Celtic–Anglian divide, a struggle between the original British and ambitious bands of incomers. Such evidence as exists suggests a more complex picture with natives fighting in Anglian armies and vice versa. What interested the kings of the sixth century was power not ethnicity.

With the departure of the legions and the remnants of the imperial administration of Britannia, the apparatus of government quickly faded away. Bureaucracy, record keeping, tax collection, a money economy, organised trade, the upkeep of services and the maintenance of towns by their agricultural hinterland began to crumble and fragment. Power shifted towards kings, mostly native aristocrats who had never lost their identity or prestige throughout the long centuries of Roman occupation and who commanded war bands to enforce their authority. It was personal and often fleeting, rising and falling with the death or success of individuals in warfare. Kingdoms were not formal administrative entities with frontiers and differing cultures. Instead, they formed around charismatic and aggressive kings and were measured only by the extent of their military reach.

For these reasons, a political geography of Scotland and North Britain after 410 can only be provisional, subject to continual modification and, in any case, based on little more than scraps of historical evidence. Or it can be entirely mysterious. One scrap talked of an early Anglian presence on the fringes of Berneich in the second half of the fifth century. Nennius noted that a war band led by a man called Eosa had established itself somewhere between the Tyne and the Tweed and, more, that he was the progenitor of Anglo-Saxons who would be kings. Another tradition asserts Eosa as the grandfather of Ida of Bamburgh.

These warriors may well have been descendants of foederati, mercenaries imported by the imperial government in the fourth century to protect Britannia from the raids of the Picts and the Scots from the north. More material from the History of the Britons adds to this impression. Northern foederati based in the Vale of York and led by a man called Soemil were said to have been Angles. Ambitious and vigorous, they ‘first separated Deira from Bernicia’. Corresponding roughly to the old county of Yorkshire, Deira had been a native kingdom with a name something like Deor, Dewr or Deifr. It gave its name to Dere Street, the Roman road that began at the gates of York and led north as far as Edinburgh. By ‘separated’, Nennius probably meant a takeover, with Soemil and his men detaching the kingdom of Deira from a greater Bernicia and assuming control. This probably happened in the early sixth century and the accession of Ida at Bamburgh in 547 appears to follow a pattern repeating all over the old province.

If these early northern kingdoms were indeed the joint creations of native and Anglian aristocrats and their war bands, they were always led by men who bore English names. That does not necessarily mean that they were, in fact, ethnic Angles, only that Anglian culture and language were in the ascendant. Military prowess may have been the blunt impetus behind that and, while records of who fought for whom and for what are very scant, one example intrigues. When the armies of the Gododdin, the kingdom of the Lothians and probably the Tweed Basin combined with their allies and rode south to meet an Anglian host at Catterick around the year 600, they were led by Yrfai map Golistan, Lord of Edinburgh. His name looks and sounds Celtic but, in fact, the second element is only a thin disguise and it means ‘son of Wulfstan’. The sources say that Yrfai was not a nobleman and it seems that, instead, he was a soldier of Anglian descent, perhaps a professional commander.

The takeover of Britannia and its patchwork of Celtic kingdoms in the two centuries after 450 is a remarkable story given the relative numbers involved. A native population of two to three million was subdued by a series of incoming war bands of no more than 200,000 in total who arrived over a long period. How they achieved so much so quickly might be explained in part by the genetic evidence.

As a result of a process coyly termed social selection, scientists have identified an old lineage in Ireland dating from around 400 to 500. Known as M222, it is astonishingly common. No less than 20 per cent of all Irish men carry it! Its distribution is heavily weighted to the north with 40 per cent in Ulster, 30 per cent in Connaught and 10–15 per cent in Munster and Leinster. No less than a fifth of all Irish men are directly descended from one man who lived around 1,500 years ago.

Given the distribution of the marker and its bias to Ulster and especially to men with the O’Neill and O’Donnell surnames, there exists a clear candidate. The Ui Neill kindred dominated Irish history from the fifth to the tenth centuries and their founder was the High King known as Niall Noigiallach. His political reach is reflected in his second name for Noigiallach means ‘of the Nine Hostages’. These were the sons of lesser kings who owed Niall obedience and they were kept in his retinue as a guarantee of continued obedience.

The simple reality is that Niall fathered many sons on many women and those sons, themselves growing up to be powerful men, followed the same pattern. Niall’s reign and his exploits are shrouded in mist and mystery but, in the historic period, one of his ancestors showed how it was done, so to speak. Lord Turlough O’Donnell, who died in 1423, carried on the family tradition with gusto. He had 14 sons and 59 male grandchildren. From this example alone, it is easy to see how a marker multiplied very quickly. If the same level of enthusiasm and fertility were sustained, Lord Turlough would have had 248 great-grandsons and 1,040 great-great-grandsons. Within only four generations and without taking any account of bastards, he could have bred an army.

The frequencies of the M222 Y chromosome group are shown across the British Isles using pie charts. Up to 3000 samples were used to create this map.

The most spectacular example of social selection was discovered in central Asia. When a survey of the DNA of more than 2,000 men was carried out, the researchers found a large group of markers which were very closely related. More than 8 per cent of the entire sample, across 16 populations in a huge geographical area from central Asia to the Pacific coasts, carried the same marker. It was possible to date its origin to about 1,000 years ago. The second-highest frequency of the marker and the place where its internal diversity was greatest turned out to be Mongolia, undoubtedly the place it came from. The lineage is unique and it is unquestionably the case that 8 per cent of all men from Uzbekistan to Manchuria, a total of 16 million, 0.5 per cent of all men on Earth, are descended from one man. And, outside this area, there are no men carrying this marker. Something remarkable has happened in the past.

Over only 34 generations, this is beyond anything seen in nature amongst animals as a result of natural selection. Statistical calculations rule out chance as an explanation. It must be the case that, not only has a dramatically sustained streak of the reproductive fitness of men with this marker been observed, there must have been large-scale elimination of other Y chromosome lineages going on at the same time. There can be only one candidate for the progenitor of 16 million men in central Asia, 0.5 per cent of all men on the planet, and that is the great warlord, Genghis Khan. He lived between c.1162 and 1227 and he and his brothers created the largest land empire in history, often slaughtering the conquered populations as his hordes rode over the plains and attacked cities and other tribes. The boundary of his empire at its fullest extent is almost exactly matched by the frequency of his marker. There is only one exception – the Hazaras of Pakistan. Their traditions claim Genghis as their ancestor and, in fact, the highest frequency of the marker is found amongst the Hazaras. It exists nowhere else in Pakistan.

Much closer to Scotland was a man who died when the great Khan was born. His exertions bore a good deal less fruit but then he operated in a much smaller area. More than 50,000 Scottish men, most of them with the surname of MacDonald or its variants, are the direct descendants of Somerled. The first Lord of the Isles and founder of Clan Donald, he ruled the Hebrides and was King of the Isle of Man. When he clashed with Malcolm IV of Scotland at Renfrew in 1164, Somerled was killed – but his genes certainly lived on.

The alleged medieval tradition of droit de seigneur – or the right of a local lord to have sex with any new bride in the community he controlled – was also known as the ius primae noctis or the ‘right of the first night’. The idea that a lord might be powerful enough to insist that he should deflower a new bride before a new husband has long been thought little more than a male fantasy. But DNA studies do suggest that something akin to most teenage boys’ wildest dreams did go on throughout history. While it is unlikely that seigneurs exercised their droit in quite that way, with each new bride, it is certain that they had productive sex with many women. Perhaps there was an informal ius secundae noctis.

When the church began to promote ideas of legitimacy and illegitimacy, it may have been to use these to act as a brake on what it saw as excessive lordly licence with the women in any community. Perhaps priests and monks saw such practices as potentially very socially divisive. Nevertheless, in the historic period, the chiefs of the highland clans made little meaningful distinction between the offspring of their wives and so-called bastard children. Somerled must have adopted a similar attitude. And early Irish law tracts encouraged the fathers of children ‘begotten in brake or bush’ to recognise them as their own.

If social selection went on on a spectacular scale with Genghis Khan, Niall Noigiallach and more modestly with Somerled, then it must certainly have been the norm locally. Some researchers who identified the marker R1b-Pict believe that the cluster of similarities is like that of the Genghis marker, although not so tight or so recent. It is probably a signal of social selection in the deeper past and perhaps those who carry it – around 10 per cent of Scottish men – are the descendants of prehistoric royalty who ruled north of the Forth and who were the progenitors of the Pictish nation.

Ida of Bamburgh was said to have had six sons and, in an age when the effects of a lack of contraception were balanced by the number of mothers and babies who died from complications in childbirth, that is not an unreasonable number – restrained, in fact, compared with the efforts of Lord Turlough O’Donnell. In any event, the multiplying arithmetic of power is not difficult to visualise. It may well be that the Angles, Saxons, Jutes and other Germanic groups who sailed to Britain in small boats simply outbred as well as out-fought the natives. And, if there were massacres on any scale (some are reported but the characteristic hyperbole of chroniclers is likely to have inflated the numbers of dead on the battlefields and elsewhere – Aethelfrith of Bernicia was said to have slaughtered 1,200 monks at Bangor), then the effects of social selection might have been as sweeping as they were in central Asia, even if the numbers involved were very much smaller.

With the defeat of the Gododdin armies led by Yrfai map Golistan at Catterick in 600, the next stage for the drama of Scotland’s developing story was set. Led by Aethelfrith and the descendants of Ida, the Bernicians began to push aggressively northwards and they would eventually clash with the Picts. The ancient hegemony of the Old Welsh-speaking kingdoms of the north was shrinking and would quickly coalesce around Strathclyde, a remarkable survival story. And, in the west, a new power was gathering strength. The war bands of the kings of the Scots would ride east and their ambition and acuity would ultimately confer their name on the whole country.