Northwest Europe (856–867 CE): Heightened Viking Expansion and Regional Consolidation

Expansion of Norse Settlements in Ireland

From 856 CE, the Norse presence intensified significantly in Ireland. Viking settlers, consolidating their earlier longphorts, turned fortified ship havens into flourishing urban settlements. Dublin (Baile Átha Cliath), initially a fortified Norse encampment, solidified its position as the primary Norse kingdom in Ireland, rapidly becoming a major trading and political center. Other longphorts at Limerick, Waterford, Wexford, and Wicklow also grew, significantly impacting regional trade and political dynamics.

Anglo-Saxon Kingdoms Under Pressure

In Britain, the Anglo-Saxon kingdoms continued to face relentless Viking incursions. King Æthelwulf of Wessex (839–858 CE), succeeded by his sons Æthelbald (858–860 CE) and Æthelberht (860–865 CE), maintained robust defenses against Danish raids. Despite such resistance, instability grew as raids intensified, foreshadowing the looming threat of large-scale Norse invasions.

The Arrival of the Great Heathen Army

The turning point occurred in 865 CE, marking the beginning of the sustained Norse conquest of Anglo-Saxon territories with the arrival of the Great Heathen Army led by legendary Viking chieftains Ivar the Boneless, Halfdan Ragnarsson, and Ubba. Landing initially in East Anglia, this formidable Norse force quickly moved northward, targeting the kingdom of Northumbria, which fell into turmoil with the capture of York (Jorvik) in 866 CE.

Norse Control Over Northern Britain and Scottish Isles

Viking influence further solidified across the Orkney Islands, Shetland, the Hebrides, and parts of the Scottish mainland. These territories developed into Norse-dominated communities, creating lasting cultural and linguistic influences. In Scotland, the unified Kingdom of Alba under Kenneth MacAlpin and his successors continued resistance against Norse incursions, consolidating control inland and attempting to limit further Viking settlement.

Early Icelandic Exploration and Settlement

Around this time, exploratory Norse voyages towards Iceland increased. Notably, the first significant Norse permanent settlement in Iceland traditionally dates to 874 CE, but preliminary exploration and seasonal visits intensified during the years leading up to this permanent colonization, laying foundations for future settlement.

Economic and Social Changes

The establishment of Norse towns like Dublin significantly transformed economic activity throughout the region. These urban centers fostered increased trade and cultural exchange between the Norse and native Gaelic populations, leading to a unique hybrid culture. Simultaneously, local economies adapted by focusing more on inland resources and fortified urban settlements in response to persistent Viking threats.

Religious Life Amid Turmoil

Monastic institutions, despite continuous Viking raids, managed to sustain their intellectual and religious activities, though often relocating to more secure inland sites. Monasteries continued producing important cultural manuscripts, preserving indigenous traditions and historical memories, including narratives such as the legend of King Arthur.

Legacy of the Era

By 867 CE, Northwest Europe was markedly reshaped by Viking expansion, settlement, and conquest. The arrival of the Great Heathen Army heralded profound political shifts across the British Isles, signaling the start of sustained Norse dominion over extensive areas, notably in northern England. In Ireland, urban foundations laid by Viking settlers would profoundly influence future economic and social structures. This turbulent period set a critical stage for the complex cultural synthesis and political reshaping of medieval Northwest Europe.

The legendary Viking chieftain Ragnar Lodbrok (Ragnar 'Hairy-Breeches'), finished with ravaging France, has turned his attention to England.

He lands his ships in 865 in East Anglia and proceeds north, aided by a supply of horses by which King Edmund of East Anglia has bought them off and by civil infighting between royal candidates—the brothers Osbehrt and Aelle—in the Anglian Kingdom of Northumbria.

It is claimed that here he is defeated in battle for the only time, by King Aelle II of Northumbria.

Aelle's men capture Ragnar, and the King orders him thrown into a pit filled with poisonous snakes.

As he is slowly being bitten to death, he is alleged to have exclaimed "How the little pigs would grunt if they knew the situation of the old boar!"

Alternative versions of the story say that he had landed by accident in East Anglia and there befriended King Edmund before being killed by a jealous courtier.

The murderer escapes to Denmark and blames Edmund for Lodbrok's demise.

One Viking saga states that when his four sons heard the manner of his death, they all reacted in great sorrow.

Hvitserk, who was playing tafl, gripped the piece so hard that he bled from his fingernails.

Björn Ironside grabbed a spear so tightly that he left an impression in it, and Sigurd Snake-in-the-Eye, who was trimming his nails, cut straight through to the bone.

Although these stories may not be accurate, like virtually all tales concerning Ragnar Lodbrok, his death has serious consequences.

His other sons, Ivar the Boneless (alias Hingwar) and Ubbe soon learns the details of their father's death and swear that they will avenge his killing, in time-honored Viking tradition.

Ivar and Ubbe cross the North Sea in 866, with a "great Heathen army" of Danish Vikings, sack York in November, meet King Aelle in battle, and capture him.

According to Viking sources, Ivar sentences him to die according to the custom of Rista Blodörn (’Blood Eagle’), an exceedingly painful death, but the Anglo-Saxon Chronicle for this year states merely that the Vikings “broke into the town, and some of them got in, and there was an unmeasurable slaughter of Northumbrians, some inside, some outside; and both kings were slain, and the survivors made peace with the enemy army.”

The origins of the "Great Heathen Army" can be seen in the band of Viking warriors who attacked Paris in 845, perhaps led by the legendary Viking, Ragnar Lothbrok.

They had raided the region from 850, repeatedly sacking Rouen and various smaller towns, perhaps striking from easily defended bases in the area of their depredations.

Much of the evidence for the Army comes from the Anglo-Saxon Chronicle.

Having gained experience across Europe, the army had arrived in Britain in late 865, landing in East Anglia.

Under the command of Halfdan Ragnarsson and Ivar the Boneless, with the support of Ubbe Ragnarsson, it aims to conquer and settle in England.

Norse sagas consider the invasion a response to the death of their father, Ragnar Lodbrok, at the hands of Ælla of Northumbria in 865, but the historicity of this claim is uncertain.

The army in late 866 had conquered the Kingdom of Northumbria.

The Danish forces in East Anglia in 869 battle defenders led by King Edmund at Hoxne (Suffolk).

Edmund dies a martyr here when (according to tradition), upon his refusal to abjure Christianity and divide his kingdom with the pagan Danish leader who had defeated him in battle, his victorious foe shoots him to death with arrows and also beheads him.

The Danish Vikings control one-third of England following the battle-death of King Edmund.

The Danes are resoundingly defeated on December 31, 870, by a Saxon army under Æthelwulf, Ealdorman of Berkshire, at Englefield, Berkshire, the first of a series of battles between Wessex and the Danes.

King Æthelred of Wessex, and his brother and successor, Alfred, the first English monarch to plan systematically for the defense of his realm against the Danish Vikings, war with them from 871, winning a victory at the Battle of Ashdown, in Berkshire (possibly the part now in Oxfordshire), at the beginning of the year.

Accounts of the battle are based to a large extent on Asser's "Life of Alfred", however there is some dispute about whether this is an authentic account.

Following his defeat at Wilton, Alfred pays a large sum to the Danes to secure an armistice, which they break, conquering Mercia in 872 and raiding the British southwest.