Norse Mythology refers to the Scandinavian mythological framework that was upheld during and around the time of the Viking Age (c. 790- c. 1100 CE). Complete with a creation myth that has the first gods slaying a giant and turning his body parts into the world, various realms spread out beneath the World Tree Yggdrasil, and the eventual destruction of the known world in the Ragnarök, the Nordic mythological world is both complex and comprehensive. Its polytheistic pantheon, headed by the one-eyed Odin, contains a great number of different gods and goddesses who were venerated in customs integrated into the ancient Scandinavians' daily lives.
Main sources
Peeling back the layers of history in order to form a properly detailed and accurate picture of the myths, beliefs, and customs as they actually were in the Viking Age is no mean feat, especially for an overwhelmingly oral society, as Scandinavia mostly was at the time. As such, we only have the "tips of the narrative icebergs" (Schjødt, 219) when it comes to the Norse gods.
On the one hand, we do have some genuine pre-Christian sources that preserve elements of Scandinavian mythology; most importantly Eddic poetry (poetry from the Poetic Edda compiled in c. 1270 CE, but probably dating back to the pre-Christian era before the 10th century) and skaldic poetry (Viking Age, pre-Christian poetry mainly heard at courts by kings and their retinues), preserved in later Icelandic manuscripts. The Codex Regius found in the Poetic Edda contains an anonymous collection of older Eddic poems, including ten about gods and nineteen about heroes, and although some of these tell complete myths, most of them assume – unfortunately for us – that their audience was familiar with the mythical context. The same goes for skaldic poetry; with knowledge of the myths taken for granted, for us, using these sources to create a full picture of Norse mythology is a bit like filling in a rather difficult Sudoku puzzle.
On the other hand, later medieval sources, such as Snorri Sturluson's Prose Edda (c. 1220 CE) and Saxo Grammaticus' Gesta Danorum composed a few decades earlier, reworked the changeable, enigmatic, but slightly tangled early Viking sources into much more structured accounts. Snorri's work is the main reason we have an inkling of Norse mythology and myths as a whole, but should also be read critically, as he wrote from a Christian context. However, the older Eddic and skaldic poems clearly do more justice to the dynamic and integrated role mythology actually played in Viking Age societies.
Norse mythology in Viking society
The integrated nature of the Norse mythological framework in daily life is betrayed by the word síður, meaning 'custom' – the closest concept the Old Norse language had to religion. Of course, what it was exactly the Vikings believed with regard to all these different Norse gods and the world they lived in is hard to pin down. However, archaeological evidence helps hint at personal devotion to specific gods people felt connected to, with accompanying customs and rituals being a standard part of everyday life. The sources also give the impression that the Norse gods had their own distinct personalities more so than set-in-stone domains.
In a broader sense, gods were also venerated and called upon by the whole community. Sites of potential cultic activity, for instance, may be identified by the appearance of the name of a god in place names, like in the case of Fröslunda ("the grove dedicated to the god Freyr"). Certain hotspots are hinted at by the sources, too. According to Adam of Bremen (who wrote his account - based on hearsay - c. 1070 CE) there was a great temple at Uppsala in Sweden which housed images of Thor, Odin, and Freyr, who were sacrificed to in times of famine or disease, war, or when weddings popped up, respectively. He relays how every nine years people got together there to let their long Viking tresses down during a great festival in which humans, horses and dogs were sacrificed, their bodies hanging from trees in the sacred grove. Although the archaeological record does not support the existence of an actual temple, the remains of other buildings, among which a large hall, dating to between the 3rd and 10th centuries, have been found.
There were, thus, various aspects to Norse mythology's place in Viking societies. As Anne-Sofie Gräslund words it, "Old Norse religion should not be regarded as a static phenomenon but as a dynamic religion that changed gradually over time and doubtless had many local variations" (56). Ancient Scandinavia was a world in which belief in divine powers abounded, and all of these had their own attributes and functions.
The Norse worldview only gradually changed with the emerging influence of Christianity, which becomes apparent by the second half of the 11th century CE. Even then, because Vikings were polytheistic, they simply added Christ to their already rather lengthy list of gods, and different customs and beliefs were used side by side for a good while.
Mythological worldview
The Norse worldview as we can best distill from the various sources boils down to the following general idea. There were four phases: the process in which the world - and everything in it - was created; a dynamic phase in which time is started; the destruction of the world in the Ragnarök; and the arising of a new world from the sea.
According to Snorri, before anything else existed there were the opposing realms of icy Niflheim and fiery Muspelheim (which other sources simply call Muspell). Although seemingly safely separated by the empty void Ginnungagap, the cold and heat expanded to meet after all, resulting in Muspelheim's fire melting the ice, from which two assumingly dripping wet figures emerged: the (proto-)giant Ymir and the cow Audhumla. By licking the ice Audhumla uncovered Búri, forefather of the gods, whose son Borr teamed up with giant-daughter Bestla to sire the first gods, Odin, Vili, and Vé. These three then took advantage of Ymir's convenient size by killing him and using his remains to create the world; the earth from his flesh, the sky from his skull, mountains from his bones and the sea from his blood. The first human couple, Ask and Embla, were fashioned out of two trees or pieces of wood.
With humans popping up, a new phase begins; time has started, and all the gods and other creatures and their respective realms are off doing their own thing up until the Ragnarök. The World Tree Yggdrasil, the axis of time and space, stands in the gods' home realm of Asgard while its roots encompass all the other realms, including Midgard, where the humans reside, and the giants' abode Jotunheim. A dragon of death called Nidhogg chomps on said roots, all while the three fates (known as Norns) spin the fates of human lives at the tree's base. As the Prose Edda tells it:
Ash Yggdrasill | suffers anguish,
More than men know of:
The stag bites above; | on the side it rotteth,
And Nídhöggr gnaws from below.
(Gylfaginning 16).
As if a giant tree were not enough, the surrounding sea is inhabited by the Midgard Serpent (also known as Jörmungandr), a monster who twists and coils itself around the world.
Eventually, these fairly peachy worldly conditions snowball into chaos and culminate in the Ragnarök, the 'final destiny of the gods', for which our main source is the 10th-century CE Völuspá saga. It starts with a terrible winter. The earth sinks into the sea, the wolf Fenrir (often referred to as the Fenris-wolf) breaks loose and devours the sun, and, as the icing on the already crumbling cake, mighty Yggdrasil shakes and the bridge Bifröst – the express-way between Asgard and Midgard – collapses. Understandably rattled, the gods hold an emergency council to prepare for battle against the powers of the Underworld, who are closing in. The Prose Edda heralds that:
Brothers shall strive | and slaughter each other;
Own sisters' children | shall sin together;
Ill days among men, | many a whoredom:
An axe-age, a sword-age, | shields shall be cloven;
A wind-age, a wolf-age, | ere the world totters.
(Gylfaginning 51).
Odin fights Fenrir but falls, after which the god Vidarr avenges him, while Thor destroys the Midgard Serpent but succumbs to its poison. The gods and their foes die left, right, and centre, until the giant Surtr goes pyromaniac and kindles the world-fire that destroys everything.
Luckily, phoenix-style, the destruction is not the end. Following a cyclical concept of the world, a new world rises – not from the ashes, but from the sea. Only a handful of gods are still standing, but the new world will have a new generation of gods as well as humankind, to live happily ever after.
Æsir & Vanir
The gods themselves are boxed into two families. Firstly, there is the bigger Æsir family mostly connected with war and government, which was in practice also used as an umbrella term for the main gods in general. It includes notables such as Odin, Thor, Loki, Baldr, Hodr, Heimdall, and Týr.
Secondly, the smaller Vanir family contains fertility gods such as Njord, Freyr, and Freyja. Despite them all living in Asgard, they do not always see eye-to-eye - which, admittedly, is difficult considering Odin only has one eye, to begin with. In fact, they clash to the point of war (the 'Vanir wars'; or 'Æsir-Vanir Wars') but exchange hostages after making peace and fuse their families through marriage.
The contrast between the Æsir and the Vanir has been argued to stem from oppositions in Viking society, as the Vanir, with their focus on fertility, good harvests, and the climate, were popular in farming communities, while the Æsir were seen to advise kings, lords, and their warriors in matters of war and governance. As such, the peace made at the end of the Vanir wars might reflect the idea that society could only function through the combined powers of both social classes.
Finally, besides these two divine classes, there were also female deities known as Dísir, popular in private worship, Álfar (elves), Jǫtnar (giants), and Dvergar (dwarfs); enough to keep everyone busy, for sure. Norse mythology offers a very rich world to get lost in.