Attestations
Berserkers appear prominently in a multitude of other sagas and poems, many of which describe berserkers as ravenous men who loot, plunder, and kill indiscriminately.
The earliest surviving reference to the term "berserker" is in Haraldskvæði, a skaldic poem composed by Thórbiörn Hornklofi in the late 9th century in honour of King Harald Fairhair, as ulfheðnar ("men clad in wolf skins"). This translation from the Haraldskvæði saga describes Harald's berserkers:
I'll ask of the berserks, you tasters of blood,Those intrepid heroes, how are they treated,
Those who wade out into battle?
Wolf-skinned they are called. In battle
They bear bloody shields.
Red with blood are their spears when they come to fight.
They form a closed group.
The prince in his wisdom puts trust in such men
The Icelandic historian and poet Snorri Sturluson (1179–1241) wrote the following description of berserkers in his Ynglinga saga:
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.King Harald Fairhair's use of berserker "shock troops" broadened his sphere of influence. Other Scandinavian kings used berserkers as part of their army of hirdmen and sometimes ranked them as equivalent to a royal bodyguard. It may be that some of those warriors only adopted the organization or rituals of berserk männerbünde, or used the name as a deterrent or claim of their ferocity.
Emphasis has been placed on the frenzied nature of the berserkers, hence the modern sense of the word 'berserk.' However, the sources describe several other characteristics that have been ignored or neglected by modern commentators. Snorri's assertion that 'neither fire nor iron told upon them' is reiterated time after time, and the sources frequently state that neither edged weapons nor fire affected the berserks, although they were not immune to clubs or other blunt instruments. For example:
...men asked Halfdan to attack Hardbeen and his champions man by man; and he not only promised to fight, but assured himself the victory with most confident words. When Hardbeen heard this, a demoniacal frenzy suddenly took him; he furiously bit and devoured the edges of his shield; he kept gulping down fiery coals; he snatched live embers in his mouth and let them pass down into his entrails; he rushed through the perils of crackling fires; and at last, when he had raved through every sort of madness, he turned his sword with raging hand against the hearts of six of his champions. It is doubtful whether this madness came from thirst for battle or natural ferocity. Then with the remaining band of his champions he attacked Halfdan, who crushed him with a hammer of wondrous size, so that he lost both victory and life; paying the penalty both to Halfdan, whom he had challenged, and to the kings whose offspring he had violently ravished...Similarly, Hrolf Kraki's champions refuse to retreat 'from fire or iron.' Another frequent motif refers to berserkers blunting their enemy's blades with spells, or a glance from their evil eyes. This appears as early as Beowulf where it is a characteristic attributed to Grendel. Both the fire eating and the immunity to edged weapons are reminiscent of tricks popularly ascribed to Hindu fakirs.
In 1015, Jarl Eiríkr Hákonarson of Norway outlawed berserkers. Grágás, the medieval Icelandic law code, sentenced berserker warriors to outlawry. By the 12th century, organised berserker war-bands had disappeared.
The Lewis Chessmen, found on the Isle of Lewis (Outer Hebrides, Scotland) but thought to be of Norse manufacture, include Berserkers depicted biting their shields.
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