Three Viking Legendary Armies: Worship Odin and Desire for Valhalla
The Vikings are famous for their raiding and plundering attacks. This becomes a common mindset that the Viking warriors were simply brutal raiders and never true warriors.
The truth is that the Viking small hit-and-run attacks gradually became territorial invasions making the warband leaders earn more social status or even become kings. The Vikings did have the armies that were born for invasions and military attacks.
If you happen to google "Viking army", chances are that you will get the result of "Viking Great Heathen Army" in top one. Indeed, the Viking Great Heathen Army was the most famous Viking military group as well as listed the best because of the orderly organization and discipline.
Ragnar's sons sought revenge for the death of their great father, Ragnar Lothbrok. This was the reason why the Vikings formed Viking Great Heathen Army
In the Anglo-Saxon chronicles, it was known as the Great Heathen Army led by four sons of Ragnar Lothbrok. The leaders were possibly Ivar the Boneless, Hvitserk, Bjorn Ironside, and Ubba. All of them, according to the Legends of Ragnar Lothbrok, were the sons of Ragnar - a great Viking hero.
The Viking Great Heathen Army invaded and attempted to conquer Anglo-Saxon kingdoms for 14 years. The source of Anglo-Saxon didn't mention why the Vikings invaded. Yet, the legends of Ragnar's sons claimed it was a revenge.
King Ragnar was allegedly executed in a pit of vapes and the executor was King Aella of Northumbria a part of Anglo-Saxon kingdoms. There, Ragnar's sons formed the Great Heathen Army and set out to seek revenge for the death of their great father.
Another famous Viking military troop was the Jomsvikings that lived around the 10th or the 11th century. This was a transition and sensational phase because the Vikings started converting themselves into Christians abandoning their ancient pagan belief.
The warriors in Jomsvikings worshipped Odin and desired to go to Valhalla when they died in battles. They followed a very strict code of conduct. No man under 18 was allowed to join the army, the only exception was Vagn Akesson who was admitted to the army when he reached 12.
Legend had it that the Jomsviking army was formed by Palnatoke who devoted his whole life for the pagan belief. Palanatoke was a chieftain under the reign of King Harald Bluetooth.
Battle of Svolder (circa 999/1000)
Because of the conflict in belief, Harald Bluetooth and Palnatoke were seen as enemies. Harald Bluetooth was among the first Viking king that converted himself into Christians (possibly because of political reasons). However, many Vikings including Palnatoke couldn't tolerate the fact that their leader abandoned their ancestor belief. Then what had to come finally came, the war was waged, blood was shed, and King Harald was overthrown by Sweyn Forkbeard.
Sweyn Forkbeard was a son of King Harald Bluetooth yet raised up by Palnatoke. Then Palnatoke formed the Jomsviking and the army allegedly lived inside the Jomsborg.
Viking berserkers were the Viking warriors who fought in a trance-like fury. Legend had it that the berserkers wore the skin of bear to join battle. Some accounts told that they left their chest bare, wearing no armor and joining the battle. Some scholars claimed that the berserkers were the warriors bare of shileds or without shield.
They worshipped Odin and also wanted to be ascended to Valhalla when they died in battle.
No armour needed when the berserkers joined the battle. They were thought to fight in a trance-like fury, knowing nothing but killing the foes.
Snorri Sturluson a famous Icelandic historian mentioned the berserkers in his work:
His (Odin's) men rushed forwards without armour, were as mad as dogs or wolves, bit their shields, and were strong as bears or wild oxen, and killed people at a blow, but neither fire nor iron told upon them. This was called Berserkergang