Scandinavian warfare conducted outside the homelands must have been influenced in terms of strategy and tactics by those of their opponents. There was no uniform, Viking method of warfare. Scandinavians and their Celtic, Germanic, and Slavic antagonists were possessed of a comparable range of offensive and defensive personal equipment and normally fought land battles on foot. Western European written sources offer a few pointers in the direction of pre-battle manoeuvres and formations. The most important strategy in this context was to avoid pitched battles whenever possible. Vikings were perceived to be vulnerable in open country, as the Anglo-Saxon Chronicle observes, especially when their whereabouts was known, depriving them of the element of surprise. In 876 the Danish great army slipped past the West Saxons on its way from Cambridge to Wareham and subsequently ‘stole away’ from Wareham by night. Similarly Guthrum’s part of the same army arrived at Chippenham in January 878 ‘by stealth’. Four years later, in another winter manoeuvre, Danish Vikings were able to follow tracks left in the snow by departing Franks. On occasion it proved necessary to disencumber themselves before undertaking military operations, as when in 893 and again in 895 the Danes placed their womenfolk (many of them probably English by birth), ships, and other property in East Anglia for safety. Horse-mounted scouts were no doubt used extensively by armies in general, including Viking ones, but they are rarely indicated in our texts. Whenever a pitched battle could not be avoided, it was essential of course to choose one’s ground to advantage and to appear resolute. If we are to believe the annalists recording events in 1003, Sven Forkbeard’s army was able to look that of Ealdorman Ælfric in the eye, and to cause the English war-leader to feign illness and his men to disperse.
Great set-piece battles of the Viking Age, such as Brunanburh (937), Clontarf (1014), and Hastings (1066), were probably preceded by quite elaborate marshalling of troops. At Ashdown the Danes formed themselves into two divisions, one led by two kings and the other by all the jarls. According to a description of the second battle of Corbridge in the Annals of Ulster, there were four batallions of Vikings, all under different leaders. One of these commanded by Ragnall, the king of Waterford, lay in wait out of sight and its assault on the Scottish rear won the day. The shouted negotiations that preceded the poetic account of the battle of Maldon may or may not reflect historical actuality, but at least the precise site of this heroic episode has been identified with a fair degree of certainty. An element of surprise would have been decisive on many an occasion. Guthrum’s defeat at Edington in May 878 was brought about in this way. From the Danes’ perspective, King Alfred’s mounted force crossing over the north-western angle of Salisbury Plain at first light would have been invisible until it came charging down the steep scarp of Edington Hill. After what may have been a relatively brief military encounter, the Danes retreated northwards to their fortified encampment at Chippenham, where they surrendered a fortnight later. Similarly Harald Haardrada’s Norwegians were taken by surprise at Stamford Bridge. Contrary to their popular reputation, Viking armies were frequently beaten. An analysis of battles against the Irish in which Dublin Norsemen participated, down to and including the epic contest at Clontarf, places them on the losing side far more often than not. One obvious reason for this is that they were outnumbered and, in hand-to-hand fighting, numbers count. Irish annalists describe the losers’ fate in matter-of-fact language: in 926, for example, 200 Vikings were beheaded; in 948 the survivors of another major defeat were taken prisoner and no doubt sold into slavery. Lurid Viking methods of dispatching vanquished warlords, especially blood-eagling, belong to the realm of imaginative literature.
The commonest types of warfare in which Vikings engaged assumed the low-level forms of raiding and skirmishing. Many of these casual encounters with local forces and even local populations occurred as Vikings sought food and human captives. The detailed account in the Annals of Fulda for 873 of a raid by an inveterate Viking called Rudolf implies that the tactic was to kill the menfolk in the Ostergau of Frisia and then to take possession of their women, children, and property. In 917 Danes based at Leicester and Northampton made a night-time raid southwards, capturing men and cattle. When monasteries were targeted by Vikings some of their victims were undoubtedly monks, but others were probably members of local defence forces. Irish monasteries were repositories not only of ecclesiastical treasures but also of the wealth of laymen, who would have tried to protect it. Christian armies were sometimes led by abbots and bishops with relatively small forces at their command. In 882 Bishop Wala of Metz made a rash attack on Danish Vikings and brought upon himself both death and posthumous censureship by Archbishop Hincmar of Reims for having taken up arms. Nonetheless in the following year Liubert, the archbishop of Mainz, also with a small force, killed a number of Vikings and recovered their plunder. In northern France in 859 we hear about a sworn association of ‘common people’ who fought bravely against Danish Vikings, whilst in 894 a raiding party returning from the siege of Exeter was put to flight by the townspeople of Chichester. Low-level warfare was probably the norm in the vicinity of the greater Russian rivers used as trade routes, where Swedish Vikings (Varangians) conducted regular forays in order to gather tribute in the form of furs, honey, skins, and wax, and of course slaves, for sale in southern markets.
In the vastness of Russia, ships remained the only feasible means of longdistance transportation; so essential were they that ingenious methods were devised for hauling them over watersheds and around the Dnepr rapids. But in the narrower confines and more open landscapes of Western Europe, horses were used extensively by Viking armies. The Danish great army spent the winter of 865–6 in East Anglia equipping itself with horses; after its defeat by the Franks at Saucourt-en-Vimeu in August 881 it did the same; and in 892 it crossed over the English Channel from Boulogne ‘horses and all’. The section of the army that returned to England in late 884 was subsequently deprived of its Frankish horses by King Alfred’s relieving force. In an earlier phase of the Alfredian wars, Guthrum’s Danes had outridden the West Saxons on their journey from Wareham to Exeter. A great deal of Viking raiding conducted overland depended on horses for mobility as well as convenience. In 866 about 400 Vikings, allied with Bretons, came up the Loire with their horses and then attacked and sacked the town of Le Mans. A detail from the Annals of Ulster illustrates in a precise way the power of the horse: on 26 February 943 Dublin Vikings defeated and killed the energetic northern king, Muirchertach of the Leather Cloaks, whose chief church at Armagh 56 kilometres away was plundered by them on the very next day. Not surprisingly that most exploitative of late Viking Age commanders, Sven Forkbeard, was provided with food and horses by the cowed and war-weary English in 1013. Having left ships and hostages with his son Cnut, Sven rode with the main part of his army around southern England, taking more hostages, with the result that by the time he ‘turned northward to his ships… all the nation regarded him as full king’. Æthelred II’s kingdom had been conquered on horseback over half a century before the battle of Hastings!
England was won by Danes by different military tactics from those used by Normans, their Frenchified descendants. Nevertheless the Bayeux Tapestry shows Norman cavalrymen holding spears aloft like javelins, as well as under arm in couched-lance style. Horses were often at or near the scene of military actions involving Vikings. At the siege of Buttington, situated where Offa’s Dyke meets the Severn near Welshpool, the encircled Danes were forced by lack of food to eat most of their horses. After Edmund Ironside’s victory at Otford in Kent in 1016, Danish warriors retreated on horseback to the island of Sheppey; their horses had presumably been stationed somewhere near the field of battle. Raiding parties would have been horse-mounted for the most part, like that conducted in Brega in the year 1000 by the Dublin Norsemen and their Leinster allies in advance of the main army of their new overlord, Brian Bórama; in the event most of them were killed by Mael Sechnaill’s men. A few years earlier, in 994, Olaf Tryggvason and Sven Forkbeard had ravaged coastal districts of south-eastern England and ‘finally they seized horses and rode as widely as they wished and continued to do indescribable damage’. After their defeat at Saucourt, Danish Vikings indulged in a Cromwellian touch: in the course of extensive pillaging, including the royal palace at Aachen, they stabled their horses in the king’s chapel. On another occasion they turned the advantages of having a steed against its aristocratic rider: according to the Annals of St-Vaast and Regino of Prüm, the east Frankish margrave Henry rode headlong into a pit excavated in advance and was there killed. The same ruse finds a literary echo towards the end of Orkneyinga Saga, where Sven Asleifarson is entrapped in a Dublin street.
In populated areas outside the homelands Scandinavians were vulnerable, whether operating as raiders, traders, or settlers, or some combination of these activities. Just like their victims, Vikings needed protection and security. To start with, their most precious possessions were the ships by which they arrived. Naval encampments designed to protect these were such a novel and distinctive phenomenon in mid-ninth-century Ireland that a descriptive word was coined from two Latin components. A longphort (plural longphuirt) is expressive of ship defence and among the first recorded examples were those at Annagassan (Co. Louth) and Dublin. Naval bases of this kind had the immediate effect of extending the range of inland forays in 841—about 120 and 90 kilometres, respectively. Natural islands were ideal as lairs for fleets, since elaborate defences would not have been required. Some of these were relatively large and situated off the coast: good examples are Noirmoutier in western France and Sheppey and Thanet in south-eastern England. Other island bases were smaller and upriver or, in Ireland, in big lakes and inlets such as Lough Neagh and Strangford Lough. Provided they had adequate supplies, Vikings could feel tolerably safe. In 863 a party of Danes withstood a two-pronged siege for several weeks on an island in the Rhine, despite the fact that it was winter-time, before retreating. Adrevald of Fleury gives us the clearest written account of such a base, on an island in the Loire near his great monastery. Here Vikings secured their ships, erected huts to live in, and kept prisoners in chains, and from here they ventured on plundering forays aboard ship and on horseback. Major naval bases attracted the covetous eyes of other Vikings: in 851 Norwegian Dublin was ransacked and burnt by Danish Vikings; ten years later a substantial ship-borne force attacked the Danish fort on the island of Oissel in the Seine upstream from Rouen.
To identify and to investigate archaeologically relatively short-lived encampments, and thus to describe their design, has not been easy. The standard Viking practice was probably to excavate a ditch and to build a bank inside it, as at Repton; indeed the Danish fort under construction at Louvain at the time of the Frankish assault in 891 was surrounded by a ditch ‘after their fashion’. According to Asser, the winter camp at Reading had gates and extensive use was presumably made of timber for such purposes. The site at Jeufosse selected by Danes in the winter of 856–7 is praised by a Western annalist for its excellence as a base-camp. At Nijmegen in 880–1 they did even better, taking over the king’s palace and building fortifications that proved to be too strong for the royal army. On the other hand, a year or so later, having barricaded themselves in a large farmstead at Avaux in the Low Countries, predatory Vikings decided to decamp by moonlight, but were subsequently defeated on their way back to their ships. Winter camps had to be stocked with provisions, a necessity that exposed the aggressors themselves to attack. The Fulda annalist tells us explicitly that the Frankish tactic at Asselt on the Meuse in 887 was to ambush unsuspecting Vikings outside their stronghold. Two years earlier a war-band took control of Hesbaye and its hinterland, gathering crops of various kinds and assembling a workforce of male and female slaves, only to find itself besieged, deprived of its supplies, and forced to make an overnight escape. Similarly, an English army obliged the Danes to abandon Chester towards the end of 893 by seizing cattle and by burning corn or feeding it to their horses.