From raids to armies
For much of the 9th century, Scandinavian attacks on England were seasonal raids on coasts and rivers. Things changed around the middle of the century, when larger forces began to overwinter in England instead of sailing home. Winter camps allowed them to gather supplies, collect tribute, and begin campaigning early in the next season.
The best-known force is the one the Anglo-Saxon Chronicle calls the “great army” (the Great Heathen Army in modern writing). It is usually said to have landed in East Anglia in 865. The Chronicle was compiled on behalf of the West Saxon court and by churchmen, so it is informative but not neutral, and it tends to present the English viewpoint. Historians also debate the army’s size. Estimates differ widely, and it is safer to think of it as a substantial force rather than a specific number.
The kingdoms fall one by one
England at this point was a group of kingdoms, among them Northumbria, East Anglia, Mercia and Wessex, which often rivaled each other.
East Anglia. The army made peace in return for horses and supplies, then moved north.
Northumbria. The army took York around 866 or 867. Northumbria was in the midst of a dispute between rival claimants for the throne, which may have weakened its response. Both claimants were reportedly killed in an English counterattack on York. Afterward, a Danish-backed ruler was installed, and the region’s political landscape changed.
Mercia. The army went south into Mercia and wintered at Nottingham. The Mercian king, with help from Wessex, chose to negotiate rather than fight a decisive battle, and the Danes withdrew.
East Anglia again. In 869 the army returned to East Anglia, and King Edmund was killed. Later tradition made him a martyr and saint, with details about his death that are legendary. East Anglia was left without an independent king.
In the early 870s the Mercian king Burgred left the country, and the Danes installed a successor who appears to have been compliant. Mercia was later divided, with the eastern part under Danish control and the west remaining under an English ruler.
Wessex holds on
Wessex was the next target. In 871, called by some a “year of battles”, Æthelred of Wessex and his younger brother Alfred fought a series of engagements. The English won at Ashdown, and lost others. Æthelred died in the spring and Alfred took the throne. He bought peace and concentrated on survival.
By the later 870s some of the Danish army had begun settling in Northumbria, and in Mercia, instead of simply campaigning. Another force under Guthrum attacked Wessex again in 878, and the crisis ended with Alfred’s victory at Edington. What followed, including the treaty and the division of the land, belongs to the story of Alfred and the Danelaw.
Why the English kingdoms struggled
Historians offer several reasons, none decisive on its own:
- Political division. Kingdoms and claimants often acted separately, and sometimes against each other.
- Mobility. The Danes could choose where to strike and where to winter, and could use rivers and Roman roads.
- Tribute. Paying them to leave was a rational short-term choice, even if it funded further campaigns.
- Local weakness. Defenses were mainly local levies and aristocratic retinues, not standing armies.
Resilience matters too. Wessex’s rulers could tap a larger base of land and followers than the smaller kingdoms, and their reliance on shire forces proved flexible.
What settlers did next
In 876 and the years after, parts of the army are said to have “shared out” land and started to farm. This is a good example of a campaign ending in settlement. The Scandinavian presence is visible later in place names, coin finds, sculpture and laws, though archaeology shows less evidence of mass migration than the Chronicle might suggest, and the number of settlers is debated.