The Northman opens with black wings over gray water. Ravens fly above wooden ships that sail toward a distant island. A boy in a red cloak—seemingly the only color in the stark landscape—stands by the shore, waiting for his father.

By the movie’s end, a different shade of red has overtaken the screen. As fire burns and a battle rages below a volcano, director Robert Eggers’ tightly packed world falls away into nothing but smoke and blood.

In the roughly two hours between these scenes, The Northman does everything it can to pull the viewer into a medieval landscape that is both familiar and strange, grounded in the physical world while soaring into supernatural realms that were an inextricable part of medieval Icelandic life. Cold landscapes, fantastical visions, riotous colors and violence work in tandem to conjure the Viking world. Indeed, the highly anticipated revenge story has been billed as one of the most accurate Viking movies ever made—a tall order given the subject’s enduring popularity on the silver screen.

This level of accuracy doesn’t stem from the film’s straightforward approach to “real” history. Instead, The Northman’s goal is to capture the atmosphere of the pre-modern Viking world, as conveyed in the vast corpus of surviving literature from medieval Scandinavia. Far from being accurate despite its fantastical elements, the film actually owes much of its authenticity to its portrayal of the supernatural.

“We [worked] with archaeologists and historians, trying to recreate the minutiae of the physical world, while also attempting to capture, without judgment, the inner world of the Viking mind: their beliefs, mythology and ritual life,” says Eggers in a statement. “That would mean the supernatural would be as realistic as the ordinary in this film—for so it was for them.”

The Northman is based very loosely on the story of Amleth, a supposed (but likely fictional) Viking prince most famous today as the basis for William Shakespeare’s Hamlet. Alexander Skarsgård stars as Amleth, who seeks to avenge the murder of his father (Ethan Hawke) by his paternal uncle (Claes Bang). Aided by an enslaved woman named Olga (Anya Taylor-Joy), the prince also attempts to rescue his mother (Nicole Kidman) from his uncle’s clutches.