They had captured not only many island chains between Scandinavia and Scotland but had held onto territory in the north and around the Firth of Clyde.
Yet this existential threat would help create a process that would eventually lead to the collapse of the Viking presence in Scotland.
The Viking acquisitions in Scotland
What began as a series of raids on remote monasteries surrounding the Scottish mainland had, by the 10th century CE, transformed into the absorption of a significant amount of what is now Scotland into the Viking world.
Island chains – such as the Orkneys, Hebrides, and Shetland – had been conquered by people from Viking societies.
The strategic nature of these islands between the riches of the British Isles and the Scandinavian mainland made them a necessary objective for conquest.
Further south, the Viking presence also extended onto the Scottish mainland, especially around the Firth of Clyde and Caithness.
Yet the Viking presence was just one of several other people competing for land and territory.
The Picts, the Gaels, the Scots, and the Britons all had petty kingdoms and were in direct competition with these new Scandinavian blow-ins.
The Viking-held territories on the islands had, some scholars argue, led to a cultural decimation of the local Pict population.
The same process happened on the Scottish mainland, with the new Viking overlords ruling over a Pict, Gael, or Briton population.
This Viking subjugation of the local populations soon stiffened resistance in a most unexpected way. As Isaac Newton wrote, for every action, there is an equal and opposite reaction.
Merger of the kingdoms
Since Rome's withdrawal from the British Isles in the 4th century CE, many different tribes and peoples had carved out areas of what is now modern-day Scotland.
The Viking presence, from the 8th century CE onwards, then, should not be seen as particularly extraordinary; they were just the latest in a long line of different peoples, ethnicities, and civilizations to inhabit this bonny part of the British Isles.
The Gaelic kingdom of Dál Riata, based around the west coast of Scotland and, at its zenith, included much of north-east Ireland, emerged as the most important of several petty kingdoms by the 9th century CE.
Academics today argue whether the traditional history of the rapid absorption eastward, gobbling the areas that the Picts dominated, is true or whether this was more of a gradual process, taking generations.
Furthermore, the effects of the Viking raids and soon colonization of areas in the north and west, traditional areas of Pictland, may have had their effect on the rise of Dál Riata.
By 843 CE, however, when a new king of Dál Riata, Cináed mac Ailpín (Kenneth MacAlpin), was crowned, he oversaw the absorption of Pictland to form what historians have called "The Kingdom of Alba."
Yet it would be another five decades before we have our first record of a "King of Alba," Donald II, who died in 900 CE.
Dunadd Fort, which was the capital of the Kingdom of Dál Riata. Photo: bonoc / Shutterstock
The Norse Gaels and the Jarldom of Orkney
The merging of Pictish and Gaelic cultures was not the only ethnic and cultural mixing going on in Scotland.
By the 10th century CE, a new ethnicity was emerging in the Viking-held areas of Scotland - the Norse Gaels.
Whilst they might have started out as bloody overlords on the many Scottish islands that experienced early Viking raids, the process of the absorption of these areas into the broader Viking world was complete by the 10th century CE.
Colonists from Scandinavia soon started arriving and intermarrying with local Gaelic populations to produce what historians have called the "Norse Gaels."
These people would dominate the Viking territories in Scotland - (and also much of the island of Ireland) until the arrival of the Normans in the 12th century CE.
A new set of Norse colonists would arrive from the late 9th and into the 10th century CE, thanks to events back in the Viking homeland.
Harald Fairhair's unification of the Kingdom of Norway during the late 9th century CE did not just stop with the Norwegian mainland.
Fairhair had his eyes on the islands of Orkney and Shetland – populated by this time with Norse Gaels – and claimed them for the Norwegian crown.
Many of Fairhair's enemies in Norway had, following his victory at Hafrsfjord, fled to these islands to escape, adding a new military elite.
Rather than antagonizing his enemies, Fairhair subdued this new warrior class by making many of them Jarls, a new ruling class for these islands.
The expansion of Scandinavian Scotland
The zenith of the Viking presence in Scotland would coincide with the life of perhaps the most important Earl of Orkney, Thorfinn Sigurdsson, sometimes known as "Thorfinn the Mighty."
He was typical of the new Norse-Gael elite, the son of Jarl Sigurd and the daughter of a King of Alba, Malcolm II.
Though his life story is steeped in legend and lore – he is mentioned heavily in the Heimskringla and Orkneyinga Saga – there is some historicity to his rule.
Born at the turn of the 11th century, he would have to wait until his mid-20s, by about the 1030s CE, to rule in his own right.
The Heimskringla mentions that he was one of the most powerful Earl of Orkneys, expanding his rule to include the Hebrides and as far south as Caithness and Sutherland.
He also was said to have warred constantly with the Kingdom of Alba, but there is scant historical detail to back this up. Nonetheless, it is evident that his extension of the Norse presence in Scotland would have ruffled a few local feathers.
However, his influence was not only in the political realm. He was said to have gone on a pilgrimage to Rome in his later years and was instrumental in the widespread adoption of Christianity in the Orkney and Shetland islands amongst the local Norse-Gael population.
His death, in about 1065 CE, conveniently coincides with the traditional end of the "Viking Age," but this was not the end of the Viking story in Scotland.
The military defeat at Durham led to Duncan's assassination by an Earl of Moray, Macbeth, who became the inspiration for William Shakespeare's most famous play, some five centuries later. Photo: Alex Kosev / Shutterstock
The Kingdom of Alba and the end of the Scandinavian influence
Whilst the rule of Thorfinn the Mighty was the highwater mark of the Viking presence in Scotland, his death did not spark an immediate collapse.
By the mid-11th century CE, the Kingdom of Alba was in a period of crisis. King Duncan I had been defeated by the English at Durham and had seen the Viking presence creep further south and south.
The military defeat led to Duncan's assassination by an Earl of Moray, Macbeth, who took the crown for himself.
This was THE Macbeth that was the inspiration for William Shakespeare's most famous play, some five centuries later. His rule lasted until 1057 CE, when he was eventually succeeded by Malcolm III.
His 35-year reign saw the arrival of the Normans, following their victory at Hastings in 1066 CE. He would be the first ruler to refer to himself as Rex Scottorum, the King of the Scots.
Yet Malcolm, despite his new title, did not rule over all of what is now modern-day Scotland. There was still a Scandinavian presence on the Scottish islands until the mid-15th century CE.
The final Norse-Gael jarl of Orkney died in 1236 CE, whilst the new earldom was then directly appointed by the Norwegian monarch.
The marriage of James III of Scotland to Margaret of Denmark would lead to the final erosion of the Scandinavian presence in Scotland.
Margaret's father, Christian I, could not provide a dowry for the marriage, so what the Norwegians called the Norðreyjar (Northern Islands – the Scottish island possessions that had been conquered in the 9th century CE) - including the Jarldom of Orkney – would pass into Scottish hands.
From then on, the Earl of Orkney was appointed by a Scottish and not Norwegian king.
The many islands of Scotland still have cultural and linguistic connections to Scandinavia, despite more than five centuries of Scottish rule.
Fire festivals – with their origins dating back to the Viking presence - are held in many communities on the Shetland islands every year.
Some of what many assume are the most Scottish of surnames have the Vikings to thank for their origins. For example, MacLeod – from the Gaelic Mac Leoid means "The Son of Lotr," whilst the common Scottish surname "Cawley" stems from Norse, "The Son of Olaf."
Perhaps the most impressive place to see the Viking presence in Scotland are the remains at Jarlshof on the mainland of Shetland.
Excavations have revealed that this area was inhabited by a Norse community, who lived here from the 9th to 14th centuries CE and constructed many buildings, including a longhouse.
Finally, Scotland only last year opened a new "Nordic Office" which hopes to promote Scottish interests in the once-Viking homeland.
A recent museum exhibition highlights the Viking presence in Scotland; more information on this can be found on the Aberdeen Live website here.
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