So they weren't really so fearsome?

Apparently not. Historians at a recent conference in Cambridge claim there was a lot more to the Vikings than pillage. Most of the seafaring peoples who came from Norway, Sweden and Denmark between the 8th and 12th centuries – the 'Viking Age' – were farmers and merchants, rather than violent raiders, and wherever they settled they brought advanced skills in leather and wood-work and soon integrated into local communities. You might even call them 'progressive'. Women, who were free to trade and participate in political and religious life, were afforded considerable respect, as witnessed by the riches found in their graves. Vikings were also in touch with their softer side, fussy about appearance and hygiene and very fashion-conscious. Archaeologists find more Viking combs than either swords or axes.

So how did they acquire their evil reputation in Britain?

The first recorded Viking landing was in 787, when three ships from Norway landed in Dorset. According to the Anglo-Saxon Chronicle, compiled more than a century later, the man sent to meet them was chopped up into little pieces on the beach, after which Viking raids became a byword for mayhem. "Behold, the Church of St Cuthbert, splattered with the blood of its priests," wrote Alcuin of York, a religious scholar, of the sacking of the monastery at Lindisfarne, Northumberland, in 793; and over 1,200 years later, Denmark still felt the need to issue apologies for Viking raids. "We are not proud of the damages to the people of Ireland that followed in the footsteps of the Vikings," said Brian Mikkelsen, the Danish culture minister, in 2007. Some scholars maintain that the raiders made themselves crazily violent by taking magic mushrooms and that from this arose the myth of the 'berserkers', warriors who in the heat of battle were impervious to pain.

And are these stories wrong?

They're almost certainly exaggerated. While raiding was a Viking tradition – fragments of bibles from British and Irish monasteries have been found in Denmark – there's scant evidence of extreme violence. There's not one case of rape reported in contemporary sources, and when Alcuin wrote his account of the destruction of Lindisfarne, he was at the court of King Charlemagne in Aachen, more than 500 miles away. Extensive archaeological surveys at Lindisfarne, meanwhile, have failed to come up with any evidence of a massacre: no signs of burning or mass graves of monks. There are even doubts about how much the Vikings looted from the monastery. In broader terms, excavations of Viking sites do still find the odd skull split in two, but most of the surviving evidence suggests that they were peaceful settlers.

What sort of evidence?

Many Viking archaeological sites contain no weapons at all, merely brooches, needles, coins and other examples of an everyday existence. "Most people's image of the Vikings centres on their arrival and the disruption it brought, but that only continued for a very short time," says Dr Maire Ni Mhaonaigh, a professor of Celtic studies who organised the recent Cambridge conference. "Afterwards, they started building settlements and interacting with the locals." Raiders adopted the host language and, over one or two generations, took local wives, adopted local names, adapted to local social structures, often converted to Christianity and became part of main-stream society. Modern Britons, says Dr Mhaonaigh, can take a lesson from such a positive example of immigration.

If they were so nice, why invade?

The Vikings' big problem was their native Scandinavia: arable land was scarce, the seasons hostile, so they were always looking for greener pastures. And they had the technology to do so. Their longships were fast and sea-worthy, their crews astoundingly adept at navigating them. By salting and storing cod, they could make extraordinary journeys. These included the five recorded Viking expeditions to North America between 985 and 1011 and settling as far afield as Constantinople, Greenland and Newfoundland. This global diaspora is the truly remarkable thing about the Vikings: they travelled as far as the Volga River in Russia and fought as mercenaries for the Byzantine Empire, reaching North Africa, Jerusalem and Baghdad.

What about their influence over here?

Danish raids during the reign of King Alfred the Great (871-899), split England in two: Wessex and English Mercia on the one side, and the Danelaw (the East of England) on the other. Alfred and his descendants eventually reclaimed the Danelaw, but it kept its own identity. Things got even more complicated in the early 11th century, when the Danish King Sweyn Forkbeard and his son Canute invaded, defeating the English king, Ethelred the Unready, himself backed by Danish forces. Once Canute became King, even more Danes settled, so by 1066 almost all English leaders, including King Harold, were at least half Danish. Even the Normans, when they arrived, were partly Viking (Danish Vikings conquered Normandy as early as the 8th century), so at the Battle of Hastings there was Viking blood on every side. In a sense, Vikings have ruled us ever since.

So have we now changed our minds about the Vikings?

Not entirely. The authoritative Cultural Atlas of the Viking World still maintains that the Vikings attacked Britain with "startling and unparalleled ferocity". Alfred Smyth, professor of medieval history at Kent University, insists there must have been something uniquely terrifying about them. "When they got psyched up," he says, "they could butcher an entire population - something new to warfare in the early Middle Ages." In a recent letter to the Daily Telegraph, historian David Hipshon insists that attempts to reinvent the Vikings smack of trendy moral relativism. "The Nazis may have to wait a few years," he writes, but sooner or later "someone will organise a conference to highlight their technological prowess and cleanliness."