Attacks on France and Ireland increased greatly during the last ten years of the 8th century. England avoided the first big series of attacks. That changed suddenly in the 9th century, however, when for many people in northern Europe, Viking attacks became as regular as the cycle of summer and winter.
The first raiding bands consisted of anything from a single ship’s crew of 30–40 men, up to groups of 400. There is no record of larger groups than that. Most of the participants in the early raids were relatively young men. Even though they had good weapon training, these men were not skilled in strategy and tactics. They operated as independent collective groups on the hunt for slaves or booty. Despite the lack of tactical knowledge and the apparently chaotic organisation, the raids gave good returns of wealth and honour. In fact, the lack of formal military training may have contributed to the Vikings’ initial successes. They used unorthodox and unpredictable strategies, especially in combining land and sea operations, which were difficult for more organised forces to contend with.
At the start of the Viking Age, many of the bigger kingdoms in England and France had dismantled their coastal defences. This had reduced their capacity to meet the Viking threat effectively. But even with a well-developed navy and coastal defence system, they would have had great difficulty adapting to the Vikings’ strategies. While under sail, the Viking ships would normally stay out of sight from the land. When the time came to launch the attack, they would drop the mast and row quickly in towards the coast or up the rivers. Without their sails, the low and narrow Viking ships could be almost invisible until they were very close to the coast. Their shallow keels enabled them to land almost anywhere. The result of all this was that they often took sentries by surprise.
It was difficult to organise any effective defence against Vikings arriving in this way. People lived far apart, villages and towns were small, and people would need to be called in from great distances if there were to be any chance of repelling an attack. That took time. To prevent the Vikings from landing in the first place, there would need to be soldiers stationed permanently in forts right along the coast. There were few of these. Fragmented leadership also played a part. Local defence was seldom controlled directly by the king, but was left to the local leaders, who were often ineffective and who lacked the resources necessary to confront the Vikings.
The most important element for the Vikings’ success, however, was their basic strategy – outflank the enemy by approaching from the sea, and attack rapidly and forcefully, with yelling, screeching and clashing of weapons to paralyse the enemy with fear. A modern military expression, ‘shock and awe’, is a good description of what the Vikings tried to do in these raids: dominate the target zone with a rapid and overwhelming attack, accompanied with an appearance of great brutality. By these means they tried to paralyse their opponents and destroy their will to fight. As the raiding parties were usually small, it was important to prevent the population from organising a defence. Once the attack had been carried out, it was a matter of taking hold of the booty quickly and getting back to the ships.
An attack on a larger monastery or a village often followed a fixed pattern. Prior to the attack, the Vikings reconnoitred the area and identified the target. This knowledge could come from previous raids; from traders or others who had visited the area before; or from a reconnaissance party shortly before the attack. The attack had to happen quickly, so as not to scare away the booty of slaves to sell and high-ranking people to ransom, and to thwart attempts to organise a defence. The attack would probably be launched from an overnight camp not far away and would preferably take place early in the morning, before the population had properly started their daily routine.
The attack had to happen with sufficient forces and enough strength to immobilise the target. As the Vikings hoped to take prisoners who could be held to ransom or sold on the slave markets, it was important to prevent people from escaping. One group of warriors would try to take control of all potential escape routes, while another group would herd together the people they could find.
If there was time, they would now separate the prisoners into different categories. Those who could be sold on the slave markets and those they thought could be held for ransom, were taken away. The others were often set free. An ideal slave was usually a young man or woman. Older men and women, infants, the lame, the sick and mature men (who could be a security risk) were not sought after in the slave markets. People taken for ransom were often priests, shop-keepers, local leaders or members of their families. These had to be kept in the vicinity, so that ransom transactions could take place.
It was not unusual for people to be killed in the course of these raids, but outright executions of people who were unsuitable either for the slave trade or for ransom were not as frequent as the Christian sources would suggest. Why would the Vikings kill the prisoners they had no use for? They presented no military threat, and the Norse code of honour gave no credit for killing unarmed prisoners. Nor was there anything in their religion to promote killing for its own sake. Obviously, prisoners did sometimes lose their lives. The Vikings are not the only people who have committed atrocities when fired up for battle and under the effects of alcohol. It happens in all types of conflict.
In several sources there are indications that the Vikings often went to great lengths to spare the lives of the monks in the monasteries they plundered. Moreover, the descriptions of these raids bear witness that many survived. It was often in the writers’ interest to portray the Vikings as bloodthirsty as possible. The attacks were often understood as a punishment from God, a lesson to be promulgated and remembered.
After the Vikings had established control over the area and secured their human prisoners, they would start an organised search for valuables, livestock and other transportable goods. There are reports that they tried to dig up floors and ground in search of buried valuables. When they reckoned they were ready, they set fire to the place and withdrew. There was good reason for the fire. The Vikings believed in all sorts of ghosts and revenants. If you burnt down the buildings you plundered, you could feel confident that spirits would not follow you home to wreak revenge. Fire was considered the best defence against sorcery and dark forces. The whole operation would only take a few hours.
The danger to the monastery or village was not over, however. We know from the sources that the same target was often attacked repeatedly over a relatively short period of time. This suggests that the attacks were not centrally coordinated, but were probably carried out by small, independent groups who did not know where other groups had already raided. In some cases, places were attacked again after only a short time by the same Vikings, who hoped to take the population by surprise after they had taken their valuables out of hiding.
The Vikings rarely sailed by night. They depended on being able to reach land and set up a camp that they could evacuate quickly if they had to. Their preference was to set up camp on an island which would be difficult for an enemy to approach. If they stopped for the night on the mainland, they had to be able to strike camp quickly if necessary. Findings of tents and equipment, in the Oseberg and Gokstad ship-burials and elsewhere, show evidence of a highly developed capacity for mobility.
The Vikings often met tough opposition on their raids. When that happened, they would often react by scattering in all directions instead of fighting. This made it difficult for an enemy to concentrate his forces, but dangerous for him to split his forces and leave men vulnerable in isolated pursuit of individuals. The Vikings’ deployment of troops differed from the methods of the English and French, who usually advanced in large formations that provided some mutual protection for each individual. The Vikings’ main aim, on the other hand, was often to demonstrate personal courage and strength. An enemy who chose to let his soldiers engage the Vikings man to man risked defeat. So the Vikings often escaped by using the tactic of dispersal, retiring in smaller groups and in different directions, forcing the enemy either to split up or to withdraw. The Vikings would then reassemble at a previously decided location when the peril was past, and sail away.