IN THE absence of historical documentation from Scotland to compare with the Annals of Ulster or the Anglo-Saxon Chronicle, the Anglo-Saxon monk Alcuin's letter of bewildered distress to King Ethelred of Northumbria in the wake of a Viking attack in 793 on Lindisfarne must stand for the reaction of all those other communities on the fringes of northern Britain who were victims of the first furious onslaught of Viking violence over subsequent decades:
"We and our fathers have now lived in this fair land for nearly three hundred and fifty years, and never before has such an atrocity been seen in Britain as we have now suffered at the hands of a pagan people. Such a voyage was not thought possible. The church of St Cuthbert is spattered with the blood of the priests of God."
Historians have taken Alcuin's astonishment at the Viking raid at face value, yet he went on to rebuke Ethelred and his courtiers for aping heathen fashions: "Consider the luxurious dress, hair and behaviour of leaders and people. See how you have wanted to copy the pagan way of cutting hair and beards. Are not these the people whose terror threatens us, yet you want to copy their hair?" Clearly these northerners were already familiar with their visitors. What was new was the violence, and it is reasonable to ask why it happened.
In northern Europe at the time the major political powers in the world were Byzantium in the east; the Muslims, whose expansion as far as Turkistan and Asia Minor created an Islamic barrier between the northern and southern hemispheres; and the Franks, the dominant tribe among the successor states after the fall of the Roman Empire in the west.
After Charlemagne became sole ruler of the Franks in 771 he devoted himself to the subjugation of the heathen Saxons on his north-east border. In 782 his armies forcibly baptised and then executed 4,500 Saxon captives at Verden, on the banks of the river Aller. Campaigns of enforced resettlement followed, but resistance continued until a final insurrection was put down in 804. Their physical subjugation complete, the cultural subjugation of the Saxons followed: death was the penalty for eating meat during Lent; death for cremating the dead in accordance with heathen rites; death for rejecting baptism.
Several times, in the course of the campaign, the Saxon leader Widukind sought refuge in Denmark, and his accounts of Charlemagne's fanaticism must have travelled like a shock-wave through Danish territories, which included Vestfold, over the waters of the Vik in Norway. How were heathen Scandinavians to respond to this threat to their culture? Should they merely wait for the Franks to arrive and set about their conversion? Or should they fight?
War against the might of Frankish Christendom was out of the question. Feasible goals, symbolically important and, in the parlance of modern terrorist warfare, "soft targets", were the Christian monasteries – like Lindisfarne and Iona – dotted around the rim of northern Britain, which were centres of Christian spirituality and learning. And so these first Viking raiders set off in the grip of a psychopathic rage that unleashed itself on Christian "others" in an orgy of transgressive behaviour. The Annals of Ulster for 794 announced "the devastation of all the islands of Britain by the Heathens". In 795 the Isle of Skye was "overwhelmed and laid waste". Iona was attacked for a first time in 795 and again in 802. In 806 the monastery was burned down and the community of 68 killed. Blamac, an Irish chieftain's son who had chosen the religious life, took it upon himself to warn others to flee when Viking ships again appeared off Iona. He stayed behind himself to bury the relics of St Columba and was tortured to death after refusing to reveal their whereabouts.
Their geographical proximity as well as the large number of Irish who had settled in Scotland over the preceding centuries – the original meaning of "Scots" is "people from Ireland" – meant that details of Viking raids on the Western Isles appeared regularly in the Annals of Ulster. Attacks on the more remote Northern Isles were not similarly documented, but the likelihood is that the first wave of violence also involved the Viking colonisation of Shetland and the Orkneys, as well as mainland Caithness and Sutherland.
The author of the Historia Norwegie, a 12th-century history of Norway, tells us that the islands were occupied by Irish priests and Picts until the arrival of Vikings, who "totally destroyed these people of their long-established dwellings and made the islands subject to themselves". The wholesale eviction or extinction of the indigenous people is a likely explanation for the fact that the names of all towns, settlements, farms, rivers and natural features of the landscape of Shetland and the Orkney Islands are, with the obvious exception of modern names, Norse in origin. Something similar probably happened to the isolated communities of the Outer Hebrides. By the middle of the ninth century, Irish annalists had started to refer to the Western Isles as "Na hInnsi Gall" or "the islands of the foreigners".
In England, Viking bands that later became full-scale armies went on to subject the inhabitants of its four main kingdoms to 250 years of desultory warfare that culminated in a conquest. In 865 the "Great Heathen Army" arrived from Denmark. Some 15 years of warring against the kingdoms of Northumbria, Wessex, Mercia and East Anglia left them in control of England from York down to East Anglia.
By the reign of King Ethelred in the 990s, Viking armies were extracting huge "danegeld" payments – money paid in return for being left alone – with a punishing regularity. In 1012 the archbishop of Canterbury was captured for ransom and then murdered for sport by a drunken group of men under the Jutland earl Thorkell the Tall, who pelted him with stones and the skulls of cattle before finishing him off with the flat of an axe. The loss of its spiritual head brought the faltering Wessex monarchy to its knees, and within five years a Danish king, Sven Forkbeard, sat on the throne of England. By 1028 Sven's son Cnut was ruler of a North Sea empire that comprised Denmark (with Skne in the south of Sweden), Norway and all of England.
Mainland Scotland did not attract the same large-scale military interest from the Vikings and was not part of Cnut's empire. Perhaps the most lasting effect of the raiding and settling was to split the island fringe into two separate and thriving maritime power centres: the earldom of Orkney, where proximity to the Norwegian west coast encouraged men to bring their whole families to settle; and the Western Isles, where the pattern of settlement more commonly involved a young man taking a local woman for his wife.
The difference in settlement patterns is reflected in the greater density of the genetic and linguistic heritage in the Northern Isles, where early 20th-century lexicographers recorded about 10,000 Norse words surviving in Shetland and where a unique form of Old Norse known as Norn was spoken until well into the 18th century.
As late as 1758, Macaulay noted that the islanders on remote St Kilda were still speaking their own form of Gaelic with "a little mixture of the Norwegian tongue". The name itself may well be a corruption of Old Norse kelda, "well" or "spring", denoting a source of fresh water and thus an important piece of information for Viking Age seafarers, with the "St" added later in the mistaken belief that the source was named after a saint.
In 1098 formal power in the Western Isles was ceded to Norway, which retained possession until 1266 when the island chain, which included the Isle of Man, reverted to Scotland. A thousand years on, the Viking inclusion of Man as part of the Hebridean chain is still echoed in the diocesan name "Sodor and Man", from Old Norse sureyjar, "Southern Isles", in contrast to norreyjar, or Northern Isles. Shetland and the Orkneys remained Norwegian possessions until 1469.
Danish rule in England lasted less than 30 years. Another 15 years on and the memories of King Cnut and his North Sea Empire were all but wiped out by the greater drama of Duke William of Normandy's overnight conquest of 1066.
The long and uninterrupted duration of Viking influence in the Western and Northern Isles is thus unique in a British context, although after about 1100 and the establishment of the first Scandinavian bishopric at Lund in Sweden it is hardly correct to refer to "Vikings" any more, for by that time the rulers of Norway, Denmark and Sweden were always – at least in name – Christian.
This is an edited version of a longer article that will appear in the December edition of BBC History Magazine. Robert Ferguson's The Hammer and the Cross: A New History of the Vikings is published by Allen Lane next week, priced 25.