Received wisdom upon this subject is currently taken as the work done by Prof. Nicholas Brooks in his 1979 paper to the Royal Historical Society entitled England in the Ninth Century: the Crucible of Defeat. In this he compares the sizes of Danish armies as recorded by scribes throughout Northern Europe and in Moorish writings with due allowance for exaggeration for effect by the writers and reporters. He concludes that the ‘co-ordinated’ armies of post 865, i.e. the Great Army, might have been carried in a fleet of between 100 and 200 ships. But these may have been of variable sizes and may have carried horses, supplies and families. I would also argue that they would have carried very many tradesmen and women to maintain the ships and equipment, and that the soldiers were not necessarily sailors. The total number of persons carried by these ships could therefore have been in the small thousands. However, the numbers of soldiers would have been a far smaller proportion.
Prof. Brooks then compares the numbers of West Saxon defenders allegedly mobilised by King Alfred and his successors to protect Wessex after 878, thereby seeming to strengthen the case for higher estimates of Danish army size. But he alludes to the changing purpose of the Danes over the decades, and where initially they were raiders – collecting plunder – they need not be of a large size because they could intimidate with their skill, viciousness and speed by comparison to the part-time militia of the locals, in later times, when they had a need to settle the land, they needed far greater numbers to police and administer the land they had conquered.
Mention is made in the post on Torksey, Repton and the Trent of the excavations at Repton. (Martin Biddle and Birthe Kjølbye-Biddle (1992). Repton and the Vikings. Antiquity, 66, pp 36-51). This work is particularly important because it reveals the extent of the fortification built by the Danes over the winter of 873/4. It therefore gives clues as to the size of the Great Army at that location and at that time.
Repton then lay on the bank of the Trent (which has now meandered or been moved a kilometre to the north). The area encompassed by the ramparts is thought to have been about 80 x 50 metres. Although it is entirely possible, and most likely that much of the army and its followers were tented outside the ramparts. If the ramparts were a ‘last-ditch’ stronghold, it is difficult to imagine a density of occupation greater than one man or woman per sq.m and this would equate to a maximum capacity of 4000.
Here is a photograph of St Wystan’s churchyard to visualise the size of the Repton fort. It looks to me like a defensible ‘keep’ where the army could withdraw to and escape by boat if they needed to withdraw.
An alternative calculation might be to allocate 1m length of wall to each defender. This would produce a count of 240.
Yet another calculation might be that the volume of soil moved to create the ramparts. This amounts to about 2000 cu.m . If the earthworks were to be completed in, say, two days, this would demand at least 120 working men, plus at least four times as many to guard them, the ships and horses, and feed and look after them, and cutting and erecting the palings, i.e. 600.
But perhaps the Danes did not think in terms of the protection of their soldiers by the construction of these forts. Perhaps they were ‘keeps’ in which the generals and their women – and the treasury – were kept safe from their own soldiery. If so, then the calculation of the construction numbers might have the greatest meaning because the generals would have wanted a defensive structure erected as quickly as possible. On this basis, they would have needed at least 600 soldiers, workmen and other people of both genders to do the building. The size of the army and its followers that subsequently occupied the landscape surrounding the fort, however, might have been much larger.
More on this subject is covered in the later post on Torksey and Repton and perhaps the logistics of supply lines needs to be considered. From the Anglo-Saxon Chronicle it appears that it was while the army was at Repton they sufficiently intimidated King Burgred of Mercia, who was at Tamworth just upstream, to flee to Rome. So perhaps a substantial number of Danes remained at Torksey for that purpose. Indeed, it was from Repton that Halfdan split the army by retiring to Northumbria. So Repton seems to have been a place of political manoeuvring and perhaps the size of the army was difficult to identify. It seems likely that it was a loose agglomeration of gangs that might switch allegiance at any time, and perhaps there were many comings and goings. Some saga evidence, cited by Prof Biddle in his Swedish radio interview, indicates that the original leader of the army, had left it before 873 to go to Dublin.
My own view on army size is that the people who considered themselves adventurer soldiers, numbered 500 to 1000 at this time, but they needed say 200 sailors, 100 heavyweight sappers, 50 ironsmiths and shipbuilders, 50 sailmakers, ropemakers and weavers, and at least 500 food servants and slaves. But this calculation makes no allowance for wives and families. The total population at Repton would have then been something in the region of 2000 – before and after Halfdan had left, for surely there would have been a great coming and going of various gangs throughout this time; we cannot assume that the army possessed a regulated administration as does a modern army in peacetime.