The numbers involved in Viking raids on 9th and 10th century England are not easy to gauge, but it is possible to come up with some estimates. First though, it is useful to get a clearer overall picture of the raids.
DIFFERENT PHASES OF RAIDS AND THEIR FREQUENCY AND SCALE
According M & H. Whittock in ‘The Viking Blitzkrieg AD 789 – 1098’ (referring to England):
there were a number of discernible phases: from c. 790 until 866,
raids escalated in their frequency and ferocity; from 866 until 896,
these raids gave way to a conquest and settlement which involved the
overthrow of every Anglo-Saxon kingdom except Wessex
Concerning the frequency of attacks, Eric Christiansen in ‘The Norsemen in the Viking Age’ notes that:
From 834 to 884, the Frankish annals record the coming of 26 or 27
separate fleets; fewer reached England, but enough.
This may not seem like very many, but these were just fleets. Not every raid would have been recorded. Many were small raids, a warlord with a few ships, but others involved 200+ ships. Viking ships of the time are estimated to have carried between 30 and 40 men (though some ships may have been larger) so we can arrive at some tentative estimates for the sizes of raiding parties and armies when we know how many ships were involved.
RELIABILITY OF THE SOURCES
Terrifying and brutal though these raids must have been, Asa Briggs writes in ‘A Social History of England’ that
It has been pointed out recently that since many of the accounts of
Viking attacks were written by monks or priests, they may have
exaggerated the size of the attacking fleets and the violence of their
On the size of Viking forces, M & H Whittock point out that
Viking armies ....were made up of separate groups of adventurers which
coalesced in loose alliances .... Being opportunistic raiders – at
least in the period up to 866 – they would also dissolve and scatter
when opposition was too great. This made it hard to know exactly what
constituted the enemy force, since its size and form was prone to
SIZE OF RAIDING PARTIES
Viking raids on England started in the late 8th century. When referring to these groups of Vikings, the Anglo-Saxon Chronicles usually used the word ‘here’ meaning a ‘raid’. A ‘here’ meant more than 35 people. Raiding parties varied in size, depending on the resources of the warlord leading the raid. If the aim was just to grab some loot, this would be more easily accomplished by a small raiding party of not more than a few hundred.
Here are a few specific examples:
The first recorded incident was in 789 in Dorset and involved 3 ships. From this we can tentatively arrive at a party numbering between 90 and 120. However, this does not appear to have been a real raid and it seems that these Vikings may just have been overly aggressive traders. In the event, the only recorded fatality was the King of Wessex’s reeve.
The far more infamous attack on Lindisfarne in 793 was a much bloodier affair and also involved 3 ships, according to Kenneth Harl in ‘The Vikings’ lecture series. This number is also given on http://www.english-heritage.org.uk/learn/story-of-england/dark-ages/viking-raid/
In 836, either 25 or 35 ships landed in Somerset and defeated the Wessex King Egbert. A similar size force may have also landed there in 843. M & H Whittock, citing other sources, quote estimates of between 1,000 and 2,000 with the true number most likely being 1,000 to 1,100.
In the early 850s, attacks on Canterbury and London reportedly involved 350 ships, larger than anything previously recorded. If this figure is to be believed, the Viking army may have been at least 10,000 thousand strong, a considerable force for the period.
[I’ll skip the ‘Great Heathen Army’ of 865 and its immediate successors (after which there was a relatively calm period until 980) as these are well covered by Wikipedia.]
In 991, according to Eric Christiansen
93 ships ravaged the Kent coast, then appeared at Ipswich….then at
Assuming the estimate of 30 to 40 men per ship still held true, this meant a force in the region of 2,800 to 3,700
Not all Viking ships carried raiders, though. Increasingly, they brought settlers who were much more interested in farming than raiding. Harl estimates that around 20,000 Norsemen, mostly Danes, settled in the Danelaw area during the 9th and 10th centuries.
PROBLEMS DEFENDING AGAINST RAIDERS
Why were the Anglo-Saxons unable to defend themselves well?
- There was rarely any advance warning; the raiders were usually gone by the time local forces could mobilize.
- England has a lot of coastline, far more than could be defended.
- England has a lot of rivers which Viking ships could sail up,
reaching far inland and greatly increasing the number of communities
at risk – it was simply not possible to defend them all against a
In short, dealing with Viking raiders was a bit like guerilla warfare – armies are poorly equipped for it.
However, the Anglo-Saxons were not always helpless in the face of Viking raids. The chronicles recorded several instances where local ealdormen led attacks on Viking raiders who hung around longer than was wise. Later, Alfred the Great greatly improved the defensive capabilities of many communities which were vulnerable to raids from the neighbouring Danelaw area.
REASONS FOR THE RAIDS
Your question implies population as a reason for the raids.Population was only one of several factors explaining why the Vikings attacked England (and other areas). At least equally important was the growth in power of Norwegian and Danish elites at home; they rewarded their supporters with land which meant that lesser chieftains and warriors had to seek glory and wealth outside their own lands.