Robert Eggers' Viking action movie The Northman is steeped in all the in-depth historical research its director and cast did to prepare themselves for making it. Eggers himself is famous for going overboard on making sure his films are accurate to a certain time—famously, while the movie was still in test screenings, one viewer claimed you'd have to have "a master's degree in Viking history" to understand any of what happens in it. That's not exactly true of the final product, which is a pretty straightforward revenge tale of a man who witnesses his father, a Nordic king, murdered at the hands of his brother, and vows to return to the stolen kingdom one day and avenge his father's death, becoming a bloodthirsty berserker and traveling to Iceland along the journey.
But the movie is exceedingly accurate, from the types of dwellings various social groups lived in to the weapons they used to fight each other, the ancient rituals they'd use to pass on knowledge and commune with the gods, and the depictions of historical events and places. "Everything's drawn from source material," Eggers explained to Thrillist. "That's just how I like to work." Knowing every single bit of background information isn't crucial to understanding and enjoying the movie, but it is fun to see just how much effort Eggers and his team put in to recreate a lost world.
Eggers knew that the only barrier to recreating the Viking world was his sources themselves, and being aware of the historical context in which they were written: "These traditions, all the sagas and the Eddas, were written down 200 years after the Viking age or later. And we imagined that the vast majority of this stuff comes from oral tradition, but how do things change? These were written by Christians, not pagans, and some of these writers clearly seem to be idolizing a pagan past a little bit, and most of them are very suspicious of it, or a mixture of both."
If you know even a little bit of background information about The Northman, you've probably heard that it's based on the same legend that inspired Shakespeare to write Hamlet. The story of Amleth is an actual Norse folktale first written down by Danish historian Saxo Grammaticus around the year 1200, but it existed in the popular consciousness well before that. In the story, two brothers are given control of Jutland, the peninsula of Denmark, and one of them marries the Queen of Norway and has a son, named Amleth (which, hilariously, means "stupid"). The other brother jealously murders his sibling, and Amleth feigns madness to stop his uncle from killing him as well, all the while planning his revenge.
The most famous Viking age warriors were definitely the berserkers, Odin-worshiping fanatics who were used as shock troops during battle, going in to terrify whatever township was being invaded before the actual soldiers came in and cleaned everything up. It's theorized that the Norse berserkers are the origin of the werewolf myth in England, as they were said to have worn bear or wolf skins during battle—"berserkr" is Old Norse for "bearskin"—though no one knows for sure if they actually did or not. (There's plenty of medieval art to support this theory, but it also could have been inspired by overblown stories of the time.) In The Northman, Amleth and his warrior gang don wolf skins as part of a pre-battle ritual, "becoming" the animals and taking on their strength.
Tree of Kings
The characters in The Northman make a lot of references to the mythical "Tree of Kings," a sort of metaphorical birth chart in the shape of a tree that carries the royal Norse blood in its branches. Amleth has vision-flashes of the tree, which appears as a giant cosmic entity, inconceivable in size, with the souls of his bloodline hanging from the branches like fruit. It's never referred to as Yggdrasill, the Norse world-tree, specifically in the film, but there is a very interesting connection to be made here. Scholars studying the etymology of Yggdrasill's name don't all agree on what it means exactly, but it's generally accepted that it may refer obliquely to a gallows, referencing a story in the Poetic Edda in which Odin sacrificed himself by hanging from a tree ("Ygg(r) drasill" would mean "Odin's horse," and the "horse," in this context, would be the tree he hung himself on). It's fitting, then, that the souls of the Tree of Kings hang, in the movie, as if they're attached to its branches.
Odin (or, more accurately, Óðinn, as he's called in the movie) is all over The Northman, from the depiction of the berserker fanatics to the ravens that gather on the roofs of Fjölnir's houses. You even see two of them, in reference to Odin's birds Huginn and Muninn, leading the ships back home at the beginning of the movie.
In The Northman, a lot of the action is driven by the Norns—one Norn specifically, the feather-clad "Seeress" played by Björk. Depicted as three women, not unlike the Moirai/Fates of Roman and Greek mythology, the Nordic Norns saw and influenced the fates of humans. The Seeress in The Northman is always seen spinning a thread of wool in her fingers, symbolizing the fate, or life, of Amleth and everyone around him. Eggers noted this was one of the subjects on which some source material tends to diverge:
"I had someone read the script early on who was an amateur Viking historian, who said, 'You talked about the Norns spinning and weaving, but they saw people's fates in a well.' Yeah, there are some versions that just talk about the Well of Fate, but in most versions that I've read the Norns are spinning. Was that always a Viking age thing? Because spinning was such an important part of the material culture. But, it could be argued that there is a classical influence [i.e. the thread-spinning Fates]. How can we know?"
Most of the action in The Northman takes place in Iceland, which is one of the locations that was settled first by Vikings, and which is now the home of an enormous portion of Norse and Viking historic material. In the movie, Fjölnir (Claes Bang) flees there with his family, Amleth's mother (Nicole Kidman) and his half-siblings, after the kingdom he once stole from his brother was stolen from him again. Iceland had unsettled land not owned by anyone else, so anyone driven out of the Norse lands could find a place there to build a home. Amleth is assisted in his search for revenge by a blue fox, a keystone of Icelandic folklore and undoubtedly a reference to Eggers' co-writer Sjón, who wrote a myth-influenced book titled The Blue Fox.
The movie makes numerous references to a few other locations, using the period-accurate names of the time. When we meet back up with Amleth after he flees his uncle's kingdom, he's a berserker fighting in the Slavic villages of the Land of Rus', a large territory governed by the Rus' people, a multiethnic group composed of Norsemen and Slavic, Baltic, and Finnic tribes that is now mostly eastern Russia. Anya Taylor-Joy's character is introduced as "Olga of the Birch Forest," a reference to her homeland of what would become Russia, as birch trees have long been a national symbol of the country.
According to Eggers, "all the best sagas" feature the hero collecting an ancient, famous sword from a burial site, which is exactly what Amleth does in The Northman. His vision of Heimir (Willem Dafoe), his father's old friend, leads Amleth down into an old burial mound, where he fights an undead warrior for a sword that can only be drawn in moonlight. Amleth's sword has more than a few parallels to Skofnung, a famous legendary sword, which mustn't be drawn in the presence of women or in sunlight, that some sagas say was owned by Danish king Hrolfr Kraki. The sword first appears when it's stolen from Hrolfr's grave by Skeggi of Midfirth, as Amleth must do in the movie.
Valkyries and Valhalla
One of the coolest parts of Viking history are the Valkyries, deathless female warriors who carry the souls of brave men to Valhalla, or Valhöll as it's stylized in the movie, as their reward for dying in battle. We see a Valkyrie twice in The Northman, once as the result of a (period-accurate!) burial ceremony for a prince that ensures his wandering soul will end up in the right place, and again at the very end of the movie, when Amleth gets his reward.
The movie's plot leans heavily on the crucial importance of dying in battle, first emphasized by Amleth's father, Aurvandil (Ethan Hawke), when he tries to explain why he can never settle down and live out his days in peace. Amleth takes these beliefs to heart at the end of the movie, both sacrificing himself to save his family and his bloodline while also ensuring himself a seat among the souls of all the other great warriors of legend who died violent deaths, guided into the realm of the gods by a screaming woman on a flying horse.